You do not indicate where the backyard would be on your plan.

Backyard is where the windows are, behind the sink.

^ also can you give up one of the other doors - maybe the driveway one?

This is complicated by all the doorways, and you want to add another one! Where?

A logical location for a bathroom is the far right side. It could be boxed off for a private, convenient bathroom. But there’s an exterior doorway there already. If that doorway could be moved to either corner (rather than smack in the middle of the wall) it would help. See red box in picture. I guess you’re considering a half bath? You’d need at least a 5’ x 6’ space, I’d guess.

I never like pantry space outside the kitchen so maybe forgrt that part then a mud room is possible. Where is th plumbing a toilet needs to have a proper serer line so IMO that drives the bus

Open to moving the side door to driveway.
Just need an extra pantry closet. We have one in the kitchen already.

One possibility depending if you can get plumbing to that area. The bathroom could be a full bath with shower if you want to use the full 10ft width if you need it. You may also have room for laundry if you wanted to put it in this room as well.