As far as picking cameras, there are several major forks in that road that you have to consider.
1. What form factor will fit you best?
Some people just go at it with an iPhone (I'm super excited to see for myself what the new ones are capable of), you can get a mirrorless - full frame or not, you can go traditional DSLR, you can go something niche like the Fuji X100F. I have an older gen X100S and it's surprisingly good for an older camera, I have a hard time justifying buying a new one considering that it's going to be either rather expensive (although that's a relative term), or improvement will be rather marginal.
This one is also related to what you plan to shoot. Are you looking to shoot models, like your mentor? Landscapes? Travel photography? Street, city scapes? Smaller form factors are definitely a plus if you're going to be on the go a lot, but matter little in the studio. Same for the tablet/computer. If you were to travel a lot and wanting to share/edit on the go, a tablet might make sense, but if you're always editing at home/office, a full sized ergonomically positioned screen is so much better for your eyes.
2. How much are you willing to spend?
This is strongly correlated with your answer to above, as a full frame mirrorless will obviously cost more than something with a crop sensor. On the other hand, traditional DSLs are probably going to be a rather good value, especially on the used market as people are ditching them for mirrorless.
3. Which camera's ergonomics, UI and color rendition you prefer?
This is mostly a manufacturer's type of thing. For example, Sony's menu system drives me insane. As much as I found to be exceptional in image quality, I just know I will hate myself if I have to deal with them every day. Obviously, it's not the same for many people who love them. I like the way Fuji processes JPEGs when you set Velvia emulation on. I like their knobs. Nikon does not irritate me, and I can set it to provide the color and contrast that really pleases me. Some people just shoot raw and do their own processing, but it takes time to develop a routine you are happy with. For a beginner, I'd focus more on actual shooting and just do some basic post processing. You generally have the option to save both raw+JPEG, so having something usable out of camera is nice to get a sense of what you are shooting, and if you are the type to go tinker with the raw file later - you have that choice.
Now, how do you determine the answers? Well, trial and error is best way. I was recently on the receiving end of a few emails from Amazon, asking what can they do to make me stop returning so much stuff. Years ago I would be doing this with Best Buy, who had a more limited way of tracking me as a customer, now it's so easy to just order tons of gear to try and return what you don't like. Be realistic, don't place the order for something that is way out of your budget. If you like it, it will be such anguish to return it, you might decide to keep it and your bank account will hate you. And your resident household CFO, too, if you have one.
Don't be afraid to grow out of things. It's how you learn. Buying used gear will greatly reduce the financial cost of doing that.
I agree that this is a good reply regarding camera choice when just starting out.
For a first camera I'm not sure how much "which camera should I buy?" ultimately matters. You will definitely want something that can shoot RAW. You will also want something where it is easy to change important settings without digging through menus (i.e. choosing shooting mode like aperture priority, shutter priority, or manual). This is something that actually matters. Digging through menus to change shooting modes is extremely frustrating. It's also nice to have physical dials to adjust aperture if you are in aperture priority mode or shutter speed if you are in shutter priority mode. You don't want to have to change these important variables via a menu.
When you buy a camera, you are also buying into that manufacturer's system. This relates both to ease of use (i.e. that manufacturer's design philosophy regarding UI elements) and also lens offerings. When starting out, this doesn't matter so much (though the menu systems can either be intuitive or frustrating--I'm looking at you Sony in the latter regard). But even that isn't vital. With use you get familiar with how the menus work and where to go to make specific changes.
The lens options can become extremely important later on, but they are irrelevant when starting out. With experience you may find later that a certain manufacturer offers better lens choices for what you need. That's fine. It's okay to switch later on as you gain more experience and have a better sense of what you really need for your vision. But there is zero chance that your first body and first lens choice is going to lock you into any brand permanently. If you reach a point where you are considering spending serious money on a body or a set of lenses, you will hopefully know at that point *why* you are choosing one system over another or *why* you need to spend your money on a certain lens. An entry-level body with a kit lens will be a drop in the bucket financially at that point (i.e. you aren't likely to be sticking with either after a certain point). Or stated another way, switching to a different system for whatever reason isn't going to be a huge financial decision as you won't have invested much in your starting system. At that point you will (hopefully) have valid reasons to justify your purchases.
A big part of starting out in photography is learning the basics of photography. Things like composition, exposure, light. Almost any camera is a suitable tool for this. Don't obsess about brand. Don't obsess about lens or camera reviews. Place your emphasis on learning the basics of photography. As long as your camera doesn't get in the way (i.e. force you to spend time thinking about which menu you have to enter to change an important setting) it's all good.
There *are* differences between cameras and lenses that ultimately impact image quality. Or differences that make some images easier to obtain. At some point that may be important for your photography. When starting out, they aren't important.
The two things I would suggest regarding gear when starting out would be to get a "fast" prime in the "normal" focal length range (i.e. something with a maximal aperture of around f/1.8 and a focal length of 50mm with a full frame sensor (35mm with a crop sensor)). These lenses are offered for most camera systems and they tend to be inexpensive. They are very useful for general shooting and are also great learning tools.
The other thing I would suggest is getting a tripod. It's okay to start out with a cheap tripod. You can upgrade it later. But a tripod is important for many types of photography and it is also an important learning tool--allowing you to see the effects of slow shutter speeds. Some would argue to avoid buying a cheap tripod as you will almost certainly want to replace it with a "good" tripod later. While true, it is the same argument that you should buy a "good" body and "good" lenses to start off since you will probably be replacing them later.
My counter-argument would be that it's okay to spend a small amount of money for a "learning" kit that will be adequate for where you are now--learning photography. At some point down the road the "learning" kit may not be adequate for your needs. Fine. But you didn't sink that much money into it. Once you know that photography is something that you care about, you can make informed choices about what gear you really need to create the images you want (made easier by your experience using your starting gear--how is my starting gear limiting me?). But until then, I'm not sure it makes any sense to invest in "good" gear until your skills are such that you can make the best use of it.
Photography can easily turn into a money pit. Sometimes this is because one really needs specific (and expensive) gear to get the image you want. However, when starting out it is easy (and natural) to blame mediocre results on gear--if only I invest more money to buy x body or y lens, my images will then be awesome. This is almost never the case. Learn photography first and let your experience guide you in how gear purchases may improve your images. A well composed, properly exposed, and properly lit image with "inferior" gear will almost always be better than a poorly composed, improperly exposed, or improperly lit image taken with the "best" gear.
