you have a couple of options here, what makes you want to go with tile? did you just purchase home, or just start renovating?

We are re-doing the bathroom to make it accessible. Floor with vinyl tile. But need to pick tile for the drop in and shower

How big is the Floor space? and did you decide on a floor color. Lighter Colors can make the room look bigger, and darker colors can do the opposite. That can aid to your decision on the wet area surround tile. A bigger tile patten 8x10 or 12x12 makes more sense on the shower space. You have more wall to work with, then a smaller size on the adjacent tub. Don’t want the tub space to look too cluttered

Assuming your going to make the shower a corner shower with a pivot door or a Stand alone?

Sorry yes not the best photo! Left will he shower, right will be drop in tub