You seem on the younger side, with a 10yo son who will be with you for the foreseeable future. That is the one factor that really would give me pause with BRV, no matter how much you love it. 1br availability isn't nearly as hard as studios, and you are still new to WDW
DVC. I would go for 100-150 either CCV or something else that has a longer lifespan, I'm willing to bet that there are quieter rooms at CCV that will be good for you, and/or you can switch at 7 months.
Hope so! Although BLT was supposed to be in 2024 and now it's "2024-2025" so who knows ...
In the meantime, though, you could try other resorts that have the murphy beds - you may find ones you really like.