The only difference that I know of is that the State of SC has an extra tax for Out of State Investors.

Do I just have to mention it to the closing lawyers and pay an extra fee?

Qualify the lender to make sure they give you income credit on the home from the rent (usually 75% of gross); your required down will go up 5% on the 5th - 10th mortgage (ie: 20% to 25% on SFR); and you will need to keep extra reserves. 

in my opinion, I would give her a dollar amount and tell her whatever place she wants is her business. if she wants to kick in an extra $20, her business. also suggest she try to get compensation from renters insurance, and you can supplement any difference, up to a certain amount if you feel inclined.

Then again, we could just have the funds to pay it off at that point in 15/20 years and we could have paid the extra interest for no reason. 

Hi @Michael White I am currently using a great guy, David Painter out of San Diego, his company does design, draft and permit. 

Current landlord is using the 2 car garage for his own storage and neither tenant has access to it - thinking that could be a source of extra revenue either offering to other tenant for increased rent or renting the space out for storage.Currently in negotiations!

We were thinking of going FHA 203k to finance the construction, but we will have to pull permits for the loan.

So do ask your loan rep right away if this is permitted with them. 

Some commercial policies may not even offer some of the extras I just mentioned.