Heres what i was thinking

even in colder climates, plumbing should be protected... it's 2024 after all.

Is this a converted two-flat?

As long as the cost for plumbing won't break the bank (only a plumber can tell you how much it will be), your plan works if you don't care about having a separate tub and shower. If you want a tub and separate shower, you'll have to place the door to the bathroom in the bedroom and make it a pocket door. Tub at one end (outside wall - add a window if you can), shower at other end, sink and toilet on far wall as you enter from the bedroom, next to each other. The door should be across from the vanity, not across from the toilet. My primary bathroom is somewhat similar, although I have 8' to work with instead of 5.5'. You'll have room for a generous single sink vanity, but not a double, in this configuration.

I don’t know about the plumbing, but if you want a bigger bathroom, you can take over the oddly shaped closet of the second bedroom, too. (A closet that is 3’7” deep is awkward; a 24” reach-in is functional.)

Have you considered using the second largest bedroom as your primary & converting the laundry room into the en-suite? You already have water hook ups to that space. The original primary can then become a large family room since you have a LOT of bedrooms in a home with very little relaxation space. You could put a stacking washer/dryer one of the closets off the hallway or perhaps inside the odd WIC at the top of the stairs?

BTW most of the closets are not trully walk in at all. I agree the best and easiest plan would be chnsge that whole right side to a amster suite with the bathroom where the laundry is and combine tose 2 WIC to one proper sized true walkin.

I would love to change the 2nd bedroom into the master and convert the laundry to a bathroom but… the laundry room has the stairs up to the attic that will be a big kids playroom

I don't think you need to let go of your laundry room. I believe this layout would offer spacious bedrooms/closets and master bathroom:

Just to give you an idea of the size of the rooms. Note that I removed one closet and relocated the other one. I put a king size bed in the master bedroom: