For 30Y loans made to an LLC - 15%-25% down minimum depending on what type of lender you are using. 

I would be using a DSCR loan since I don’t have 2 years of work history.You are mixing up loan types and I recommend to better understand these types.

And I agree the vast majority of larger investors started with a nice amount of cash or very robust professional type salary.

Last time I did that, my costs came in right at $1000.The OP is vague because it does not address size or location of heater, type of fuel, self-install or hired, permits required or not, and whether or not they care about a specific brand.  

All are 4/4.5/2 What made you interested in investing in this type of deal?

Not sure how long you have been around, but when markets soften, these types of assets get crushed because vacancy rates increase which causes condo fees to increase due to the amount of delinquency on the books.

Depending on the type of trees we can also receive income from multiple companies once trees are producing.

No, depreciation is NOT counted against you on a full document application.

Additionally all IRA's have to, per IRS guidelines have a custodian but there are ways to avoid having to go through them for all transactions and subsequent fees by using plan documents that give you checkbook control.   

Always question the "Sales guy" when it comes to these types of things.