@Forrest Williams depending on how custom your flip is I think you will be fine.Most of the materials purchased for a basic rehab are all bought at Home Depot in my company.

If you are unable to find a strong team, go to another location.You and your team evaluate individual properties based on: price, rent, time to rent, rehab cost and risk, average tenant stay, probable maintenance cost, etc.SummaryI covered a lot of material in this post.

Tenant acknowledges the rental was represented through marketing materials designed to attract applicants for in-person inspections.

Get lien waivers for materials and work from the subs as you pay. 

Is that pricey these days and potentially risky with the high cost of materials and supply chain issues?

When I do allow it, I have the authorized work spelled out on a form that say what they are authorized to do, what materials will be used, who pays for materials or labor, limits to what will be paid, a deadline for completion, what happens to the improvement when the tenant leaves, and what happens if the Tenant fails in any regard. 

The cost of material is up quite a bit from even the start of the pandemic, SFR prices are starting to cool off, and real estate industry sectors are bottlenecked to the brim.

This also seems unlikely and far out, as supply chain issues continue to persist, build times remain extended, and material costs remain elevated.

I will look for those materials online. 

There is also the risk of a bad company earnings call or sudden material news that changes the trajectory of the stock price.