Are you detail oriented? 

Give me a call we are a very investor-oriented company. 

Or you have to add or replace a few pieces here or there.Vents - those should also all be replaced (most roof hardware is replaced, other than the gas exhaust pipes)  Which vent TYPE would be best depends on the style and cut up of the roof.

This will allow you to use your HELOC again and again for BRRR style properties

(Age, builders, style, HVAC systems, etc.)In vegas we have two giant air returns in our hallways and air registers in every room. 

This seems most effective in theory, but may be difficult, because it hinges on whether I can realistically find like-properties where the only major difference is whether its interior style is modern vs. obsolete. 

The rest of the loan you'll get will be investment style and will require you to put 10-25% down.Based on that, I'd only put down the minimum, 0-5% and save the rest to enable you to continue investing in more properties or being able to rehab out of pocket.  

For house hacking, are you referring for a one unit with many rooms and renting by room or duplex style? 

@Auria Styles I think that doing a 1031 exchange in to a larger property is a good way to go.

I am not super familiar with hard money loans, I always thought those where balloon style loans.