Like you said Heather " there is a lot to consider" I know it is exciting to start a new business, but take your time, and plan goals along the way. Set budgets, and try not to let emotions, drama, etc influence your decisions. Do you know any of the past Agency owners? Can you get their input? Not that you want to go down the same road, but learn from their mistakes.
I prefer a condo or hotel (not the cheap one's, but the ones that have lots of traffic, that look like guests) privacy is important for us all.
Hopefully we don't loose too many indy girls, from the Durham pool, to ya.

(just kidding, For me it would not matter, as I would see them through you)
There will always be some guys who will not use an agency. For a few reasons....
1.They don't like the idea of all the funds not going to the SP. (this is not my prospective, just what I have read in the past), (what the owner and the SP's agree on, is up to them)
2. Time restrictions. Indy girls tend to not "clock watch" as much as one's working with an agency. (Maybe in your agency, you will be able to give the girls a bit of flexibility on the time, if they ask for it or it is a "repeat client" )
3. I have read a few comments about indies vs agency that indy girls tend to feel more like a GFE.
I remember a SP told me she prefer to work via an agency ( less hassle on their part,etc.etc). I hope she comes and works for you, if this is a go.
One thing I like about agencies is, they post availability of their SP's. Some indies, it is hard to know or you have to keep checking BP's or duttslist , or call them.
(I kind of hate calling when I don't know their schedule)
All the best.