Homeless population and those in transitional housing

Hello ACS data users group! This is my first post.

I am working with some local nonprofits that serve the homeless population and who help people move into transitional housing. I'd like to get estimates of the size of these two populations broken down by age (broad categories) , gender and hopefully race.

There are very few Census tabulations (either ACE 5-year or the 2010 census -only a few 2020 census tables are out yet) that "break out", the individual Group Quarters type. The PCT39: GROUP QUARTERS POPULATION BY SEX BY AGE BY GROUP QUARTERS TYPE (from 2010 census) is available. This table goes down to at least the "CSD" "county subdivisiion" geography, which includes cities and towns typically.  But I need the table for years between the decennial census and having race would be very helpful

I've contacted the people at the Census about a custom tabulation with these 3 variables: group quarters type x age x sex (and possibly race - very useful) using ACS 5-year data. They seem to be receptive that such a tabulation would pass the disclosure rules at the Core-Based Statistical Areas (CBSA) geography.. The Disclosure Review Board is looking at it.  Hopefully I'll be able to spread the cost across several organizations and see if there are any grants or donations available.

Someone might suggest using a PUMS file, which has a group quarters / household flag but the group quarters type is only institutional/non-institutional so that won't work. With the "big area" tabulation I hope that I might be able to "pull down" the CBSA tabulation to the CSD level using the ACS 5 year data and some type of Small Area Estimation technique (qroup quarters subtype being the outcome in the regression.)  

Any thoughts on any part of this greatly appreciated. I'll post what I am quoted for the custom tabulation.  Also HUD, Housing and Urban Development, conducts a homeless census but they don't collect age and sex and they don't canvas people in transitional housing.

As an aside -- I was reading an earlier post about how a college dormitory might be classified based on if it was owned by the college or an outside developer.  I contacted the people at the Census about a boarding house on my street to see if it was classified as a group quarters or if the ACS used the household survey for that "structure," I was interested because a local community organization uses the building as transitional housing for the formerly homeless.  The address is in the Master Address FIle https://geocoding.geo.census.gov/geocoder/geographies/address?form but you can't get the status as a group quarters v household. That piece of information is not available to the public. I believe that the local government helps with determining the status based on the US Census guidelines . But I doubt if the guidelines are detailed enough to have a classification scheme that applies across the entire country. There has to be local input.

I use R on ubuntu

Any help on any of these topics appreciated,