I'd like to start this as a service by hand first, and progress to a web based booking and payment model if the business does well and shows room for growth.

My advice: If you are just getting started then take a lower percentage on the first few deals, prove out your model to the investor, then get a higher % going forward.

I'm not really worried about the $100k you've got in the game to get the assignment, but I'd be worried about the money you're putting in to rehab it as not generating 1:1 ROI.Maybe the Bay Area is such a hot market that it's less risky than I think, but I tend to be risk averse as an attorney. 

If that is the case, who is going to get the place ready for the next guest, similar to a hotel or Airbnb model? 

One thing to keep in mind with RE  (especially with the appreciation around here,  and hot market around tacoma)  is that time can turn a bad deal into a good one.Even if you are negative on monthly cash flow now  (occupying one unit)  you are $1250 a month less negative than if you had an owner occupied SFR with the same monthly costs,  and you are getting some tax benefits.    

And she told me how hot the local RE market is in Boise, with everything going up every day...Well, for those of us in the Bay Area, RE price peaked in 2018, and has been dropping 10% ish since....

You just need to make sure you not only have enough money for the 3.5% downpayment for an FHA loan, but also some money in reserves in case something goes such as a hot water tank or other issue. 

With Vegas being a hot market and owning nice units in nice areas, they don't last too long once vacant.

One even has an inflatable hot tub in it.

These are some of the other items that need to be budgeted for roof 25 year life span, appliances and hot water heater 12 year life span, hvac 20 year life span, bath and kitchen remodel 15-20 year life span, etc.