Receive and cash your check.

I would check with a title company to make sure you are doing it the right way. 

But here's where I'm scratching my head: this REIG doesn't seem to have a proper name or a website I can check out.

I would check with your CPA just to confirm all this! 

Most good Contrs will even be able to handle this as they will have accounts at the big box stores and cabinet shops, In these cases you should feel comfortable giving out an amount close to what he will be spending to buy your new cabinets....just get a receipt and take pictures of the check, etcBut other than cases like this, a Contr should be paid for a particular trade when it is complete (and if applicable, has passed inspection) I.E.

Their background checks came out clean.

Unfortunately I won’t be in on Tuesday but I’ll check out the group you sent.Do you fix and flip in the area? 

If you close in your name and transfer the deed after it is a SALE this can trigger the lender to call the loan, you can't get insurance to match the note and they check.

First, check out what people want and what others are charging in your area.

There are county websites that show specific insurance, water and permit guidelines that are very particular to the area (check if the area has "Flood Zone X").