Awesome trip report! I also had the chance to see the Susa group in 2012 and it was one of my favorite life experiences

I want to just point out that the actual trekking is the same regardless of which lodge you stay at, so as $750 is already an intimidating number, it is possible to not spend too much more there, depending on how much you're willing to rough it, though as op points out, the better lodges may have some pull in getting into your priority group choices (in Uganda I believe you buy group specific permits in advance)

That said, the Sabinyo Lodge looks beautiful and I also met people staying at the Virunga Lodge who seemed to love it