There no reason to wait any time or have any “whichever is lower” rule come into play.

So, make sure your closing agent will do whichever type of transaction you're planning to do.You need to be attending local REIA and real estate investor meetings to get local information and to learn who you should be using in your area.Good luck to you!

Here is how the HML I work for does it.They fund up to 75% of ARV or %90 of purchase and rehab, whichever lower. 2. all rehab loans are 12 months.

I heard as investor ideally to offer 80% of the market price or like you said at discount $10k-$15k, whichever higher.

They will lend on 70-80% LTC or LTV, which ever is less. 

The answer is simple:  Whichever offers you the best terms and lowest cost of capital. 

You could help her make some of those connections on BP by hunting down the movers and shakers in whichever markets she prefers. 

Or would it be a better approach to follow up on all warm handoffs AND leads myself, then pay a fee to whichever one I closed on?

A GC is forbidden by law to ever ask more than 10% or $1,000.00 which ever is lower up front before they ever starts working on an project and then they are limited to a 10% over and above all the costs of doing a project, market rate requirement. 

Shop here on Bigger Pockets to find them.From a commercial lender's perspective, with no commercial experience as an investor, expect to be required to put a 30% to 35% down payment + Closing Costs and reserves off of the purchase price or appraised value whichever is less.