It is not an online question. Either way, your kids look old enough to do some wash: ) The only laundry you will generate on the first floor is yours. You need a designer and a contractor to make any other arrangement.....on site. It can't be answered here.

What someone else did is not your home. A first floor /ensuite on a concrete slab that WAS a garage is your situation. A stack, side by side, storage, ....all depend on the dimensions and availability , access, expense, venting of the dryer, or a host of other issues. The on site view is what you are getting, and what you need. Along with a designer so as to not make a big mistake : ) you will later regret.

I am interested to know what the contractor says. Good luck. Keep us posted!