Help needed adding bathroom & redoing closet in new master!

Hi! We want to take down the half-walls separating the office & bedroom to make it the new master/primary bedroom. We want to add an en-suite bathroom, but not sure what the best approach would be. We're thinking of copying or mirroring the current bathroom so they're right next to each other, or having the bathroom take up that whole back portion. The windows make it a bit challenging. Don't want to go into the third bedroom, but the current bathroom could potentially be a bit smaller, which may give us some more wiggle room for the new master.

We also want to update or relocate the closets to have a walk-in, as the current layout of the two reach-ins next to each other make it hard for bed placement. There is currently a twin in the room, but we would like to have a queen or maybe a king. One idea is to take the current "primary" bedrooms back closet and add it to the back of the right closet.

Thoughts? Something else entirely? Thank you!