Hall bath seems a bit more appropriate, but you can really go either way.

I also think the shared hall bath should have the tub. It's the most probable one that would be used by children. I would guess the large bedroom would be the most used guest room and most adults would prefer a shower

I feel the opposite--no one will want to linger in the tub if they know that someone might come along who needs to use that bathroom. One is more likely to use a tub if they don't think they will be disturbed, in my opinion. Because you used the term "guest rooms," I'm guessing we're not talking about rooms that might be shared/used by resident children, which might make a tub accessible to all more practical.

How are you planning on using these rooms?

Are they actually guest rooms that would be occupied by non-occupants or are they going to be used by children?

Absent unusual circumstances, I don't think "guests" generally want to take a bath. A bath in a tub generally involves cleaning the tub beforehand as well as cleaning it after the bath itself. As a guest I also personally wouldn't particularly want to take a bath - I've never been a bath person anyway but in a strange bath it would be a double negative.

Given that I would attach the bath to the bathroom suite since it is more likely that an occupant of an adjacent bedroom would actually use a bathtub.

But really I don't think there is wrong or right - most children don't take baths after a fairly short period of time in my experience anyway.