If you want to get your license, yYes, you have to hang your shingle, so to speak, under a brokerage.

We could forgo adding a half bath, keep that as an extra if things come under budget.The siding is cedar or wood shingles on the top half of the house, so our choice would be to replace individual ones and paint them, or redo with new siding.

The shingles appear to be in good condition however the SFR has a large sagging area in the roof.  

You can likely hang a shingle and get tenants on your own.Do you own units in other areas as well or is this just for CS?

Second, I've been spending time researching how to find comps, even if you go based off of ARV and not what the seller is trying to sell the house to you at, and all the websites (which I have seen other people on here as well on BP) often have inaccurate information such as zillow etc (the free/computerized websites) And so if I don't have access to MLS or know anybody, what can I do about estimating ARV of a house?

If the roof needs replacing always opt for the lifetime architectural shingles with streak guard.  

IF it nots cedar shake, I bet you have multiple layers of shingles, In my area 2 layers and then you have to tear off. 

Houston should be the same as conroe as far as the life of a shingle roof.  30 years or so.  

She has a finance and project manager background and I am a third generation contractor (who promised his dad he would never be a contractor... sorry Dad what did you expect when you would wake me up at 5am to haul shingles and bricks up a ladder at age 14) and first generation entrepreneur.We are truly looking forward to the constant improvement environment Bigger Pockets has created here.

Hang your shingle and get to work!