We hooked up with a local reputable realtor who has guided us through the whole process as newbies.

Probably the best way is to get with a reputable contractor and try to get figures they use for estimating.

Somewhere out there, there is a video with folks from a Gun manufacturer. 

c)  helping someone bid on a manufactured home at private auction, then loaning them money from a self directed IRA for purchase + rehab costs. 

If you are working with a reputable insurance company and restoration contractors that put forth a fair bid, allow the insurance co's adjuster to have a fair shot at it first.

This would pertain to finding an investor friendly realtor, a reputable contractor, a reasonable lender, etc. 

Their SEER (~23) and HSPF (~10-11) ratings are behind the industry leaders.Their Infinity Line looks very much like other house brands manufactured by Gree (appearance and specs line-up) and boast/claim a SEER ratings of 30-42 and HSPF of (10-15) ... though their noise rating are still akin to a loud dishwasher.  

I'm a little lean right now for the course but hoping to find a reputable note seller.

red flags are this.1. too quick to approve you when you have little to no expreince2. they don't ask you for detailed financial information from you.3. rates lower than you see from bigger legit lenders ( too good to be true)4. money up front and just like what happened to you.. need this fee .. oh and now I need that fee and of course you will get funding tomorrow if you pay this fee.. this is all a scam plain and simple. find reputable HML in your market go meet them.. if you have no experience it can be tougher.. if your credit is less than 640 can be tough.. if you have no cash for a down payment.. pretty much impossible..

I would ABSOLUTELY make sure the contractor is licensed, insured and has a good reputation.