For perspective, when we were remodeling our house after it was gutted from smoke damage, we looked at adding utilities to an upstairs linen closet to turn it into a laundry room. Small '60s closet...$5500 to add power, water, drain.
I think you're good with the extra bathroom, considering water's already flowing in and out. Can always convert another room to a BR; closets are a lot cheaper to add. :thumbup: