If you get a multiport charger with a max of 100W, it may not provide enough power to charge your 16” and another device at the same time. (As another poster said, his charger outputs a max of 45W per port when two ports are used. That would likely be not be enough.)
There are some multiport chargers that have a combined output of over 100W (though no more than 100W from a single port) that may still output enough power to charge your laptop and another device at the same time.
I was just looking at a 108W 3-port charger from Satechi the other day that will do up to 88W/20W with two ports and up to 65W/20W/20W with three ports (as well as 100W with one port). 88W/20W might be enough to charge your MacBook and an iPhone at the same time. 65W/20W/20W may or may not effectively charge it, but if does, you could charge it with two phones or other low power devices. (It supports other combinations as well.) Basically, just make sure to look at the info of any charger before you buy it to see what power combinations it supports. There’s no point in buying a multiport charger if you can only use one port at a time.
Also, as far as buying a second MagSafe cable, unless you need an additional cable and would only ever use it for your Mac, there’s no reason to spend the extra money on it now when a regular C-to-C cable would work just as well. The MagSafe cable is only needed for faster than 100W charging with (as of right now) Apple’s charger.
