2) 2% for repairs seem low for a 4-unit. 3) 2% for vacancy seems low as well. 4) i would go 10%-15% overall for a vacancy and repairs budget. dependent on area and tenant base.

@Brock Smith Depending on where you live in NE, the water company will give property owner notice if the tenant is behind, just like @Josh Nix said above.

Or does it just depend on the condition  of the homes?

Varies greatly depending on level of materials and finishes but here in my area it's roughly $150/sqft.

More than likely, a municipality will provide a grant for down payment depending on your income if you're a first time homebuyer. 

I'm no expert, but I don't think having an S8 tenant should make any difference.I would recommend to buy in your personal name since that will give you the best terms on your loan and then to transfer title into an LLC or land trust depending on what your LLC structure looks like.  

Depending on your credit and experience a hard money lender may lend up to 75% of ARV.

Depends on neighborhood and tenant base 

LTV is around 30-40% depending on what I can buy it for.

It depends primarily on your business plan.