Here is some more detailed info from the Town Lake YMCA PUD filing. The PUD filing with project details was filed in early July. I missed that filing for some reason.

I'm somewhat surprised no other local source picked up on it - especially since the YMCA announced in May that a redevelopment plan was in the works.
Five buildings
1. Three towers with 425' height limits and up to a combined total of 750 RUs
2. One affordable apartment building with 90 RUs
3. The current 47.8K SF YMCA will be replaced with a new 110K SF YMCA building
4. One 10K SF retail space - most likely a restaurant - to be located in one of the five buildings
Included within the new 110K SF YMCA building:
>83K SF YMCA Facility
>13K SF Preschool
>7.5K SF Child play area
>4.5K SF Youth development center including mental health services
>2K SF Community retail (whatever that is)
A free YMCA membership for residents of the project