Here's why I ask... if you're a first time buyer you'll face a difficult challenge satisfying lender guidelines. 

You would need to consult with a (local) lender to see what is available to you for that property, but I am assuming 20-30%.You would likely have 2 options with that property - 3 2 bedroom unit listings, or 1 6 bedroom listing. 

Vinny - I would say that if you're next deal will be a BRRRR you have a couple options for finding the funding, including: 1) Taking a HELOC on your primary house assuming that when you refinance you'll payoff the HELOC, 2) You can also use a loan from someone else like a private lender (friends/family) in which you pay them 10-12% for the use of their funds, OR, 3) You can use a hard money lender in which the rates are a bit higher and there will be some points added as well.

I am in talks with a private money lender right now who is killing it as an agent and doing flips.

Would you recommend letting the mortgage lender know the LLC will be paying or is it safe most of the time to not say anything and just start paying from the LLC?

Many folks these days are opting not to work on Subto's as that strategy has become commoditized and marketed by big industry gurus which now in turn has led to the lenders taking notice and starting to call the notes due, since a subto scenario is a technical default, unless there was a formal assumption done. 

Also, are there any recommendations for investor friendly Real Estate Agents, Lenders, and Property Managers in the San Antonio areas?

This won't allow you to access much (roughly $30-45K depending on lender, I use CUTX) but it's still good to have that option available if a great deal comes up. 

You can check out hard money lenders and private money where they focus more on the deal itself than your employment. 

The biggest draws for investors are not needing to provide income docs (no W2, tax return, paystubs etc needed), DTI doesn’t matter, you can close in an LLC, and not all lenders report the debt to your personal credit (so it doesn’t affect your credit score or DTI for future conventional financing).