Okay, today I left my iMac sit for several hours while I converted a copy of my iPhoto library (the whole thing; almost 68,000 photos) into Apple Photos. It took several hours and the iMac wasn't any good for anything else while the conversion took place, but it did work!...
CLIP
Yes, of course you can make batch changes. Just select the photos you want and edit them the same way you would edit one photo. You should just make a smaller sample library and try to do the things you are asking about. Take some tests shots an import them into the sample library. If it worked on iPhoto, it probably works in Photos. Here's a very in depth tutorial. You might also call your local Apple store to see if they have any Photo workshops so you can speak with an expert. Best advice is just try it. The HELP function is also very useful. You can create and import to Folders & Albums. You can create Memories or what you are probably calling Events.
Last edited: