Since I will be doing this more with other investors that I have pre-relationship with, would it make sense to set up a bigger fund with first close being $450k, and subsequent closes to be $1M plus.

If you're willing to go after value-add deals, you could do a bit better and maybe even get your capital back after a few years to do subsequent deals.If you want something truly passive, you can consider investing in syndications.

Once the auth is in place for $10k, the lender can still capture that amount regardless of any subsequent changes to the account, including a credit line decrease, so long as the auth is still active.

Maybe an enterprising GC could make their whole career out of giving out bids for money.

Over the past year, I have worked with @Sean Richway on several deals and have been satisfied with his attractive terms and subsequent loans.