My question is how and what terms that are reasonable do you typically use?

Knowing that 30 year fixed mortgages to an LLC are definitely feasible gives me reason to explore some new options and opportunities. 

That sounds pretty risky.There's no reason for you to get any loans for him.  

We're trying to find something that is no more than 15-20 minutes from Kailua, reasonable commute to HNL, and land that will accommodate a great view.

I checked the crawlspace out a little further this morning after posting this and previously they were venting it to the outside but for some reason they uninstalled it running to an outside wall and just ran some flexible duct straight down under the crawlspace.

Existence of the pool increases your insurance premium for this same reason.

The reasoning presented is to take advantage of the deductions as a business as they would exceed any tax savings as individuals... again not sure?

It sounds like you want to also have the proceeds of the deal available to you also which is another reason to not go the self directed Ira route. 

It's just tough because due to various reasons the property has been vacant almost a year.

For 2 reasons, one the market is more inexpensive.