I've procured some of the Allure Ultra for my SFR; should be installing in the next few weeks. 

If this type of tighter controls and underwriting standards increases, what I envision happening is that those sites that are offering predominantly equity deals - those where the Sponsor has little to no skin in the game; comps aren't backed by independent appraisals; loan commitments not procured prior to raising equity capital leading to large gaps between when Investor funds are committed until they start earning; etc, etc. - will have to start offering increasing higher (i.e. riskier) returns to compete.  

However, in this type they will also execute a listing agreement with one brokerage and pay them a commission if they are the procuring cause of the sale.

if your sellers agent is the procuring cause of finding the buyer (you) there is very little he can do to get out of not paying a commission.  

You are finding the house because an agent has put it in the MLS so the agent may be able to prove they are the procuring cause of the sale if all of a sudden their client wants to cancel and sell to you.   

Broker" means an individual, partnership, limited liability company, corporation, or registered limited liability partnership other than a real estate salesperson or leasing agent who for another and for compensation, or with the intention or expectation of receiving compensation, either directly or indirectly: (1) Sells, exchanges, purchases, rents, or leases real estate. (2) Offers to sell, exchange, purchase, rent, or lease real estate. (3) Negotiates, offers, attempts, or agrees to negotiate the sale, exchange, purchase, rental, or leasing of real estate. (4) Lists, offers, attempts, or agrees to list real estate for sale, lease, or exchange. (5) Buys, sells, offers to buy or sell, or otherwise deals in options on real estate or improvements thereon. (6) Supervises the collection, offer, attempt, or agreement to collect rent for the use of real estate. (7) Advertises or represents himself or herself as being engaged in the business of buying, selling, exchanging, renting, or leasing real estate. (8) Assists or directs in procuring or referring of prospects, intended to result in the sale, exchange, lease, or rental of real estate. (9) Assists or directs in the negotiation of any transaction intended to result in the sale, exchange, lease, or rental of real estate. (10) Opens real estate to the public for marketing purposes. (11) Sells, leases, or offers for sale or lease real estate at auction. 

Doesn't mean they manage the unit, just procures the tenant.

For a bill this large, I would try to procure a second bid, if that's an option.

If you're even further on the spectrum of being "time poor" then there are companies that can probably do all of it (from selection to procurement to installation) for you as a turnkey service.

You can use a bank, although the loan structure they would likely propose if you are using the "BRRRR" strategy would be more of a bridge-to-perm type structure whereby they finance a portion of the purchase, the rehab, and then refinance on the back-end after a seasoning period.Real estate investors often use hard money lenders for the front portion of the "BRRRR", namely the Buy and the Rehab, because it is more difficult to procure bank financing if a property requires significant repairs.