Pretty much any modern smartphone will do all of the things you mentioned. You can have two or more plans and subsidized contracts under the same name, but you’ll have to check with the carriers to see if they offer any sort of shared minutes / “family” plans.
There isn’t any phone that is better specifically for Taiwan. Different people prefer different platforms. I use both Androids and iPhones day to day and prefer iPhone. It just works a lot better & easier despite what feature sheets might imply.
There are also a few stickies in this forum to help with this, as well.
Look here for evaluating what your options are depending on how long you will be staying and whether you will have an ARC:
forumosa.com/taiwan/viewtopi … 7&t=103629
Look here for evaluating and pricing out plans and contracts.