If your son is looking for 3-4 unit resi in SD, you should research the "self sufficiency rule" as it can/will eliminate many coastal properties if/where 85% gross rents don't cover PITI; does not apply to SFRs and duplex so long as DTI works out.Long time no see on BP BTW Erik ... glad to see you back and I hope all is well in Memphis.

Regarding the deposit situation, as long as you and the existing tenant that stayed are in agreement, you certainly do what you suggest. 

There is not enough info provided to determine if the transaction is prohibited or not but as long as the "borrower" is not a disqualified party, then you are fine there.

Please keep in mind that you may have prepayment penalty in your state.One of the main problem is that the interest rate is variable, so you really don't want to be in a position where you have to keep the money out very long as the rate could climb up.The other problem I have heard of but haven't had time to investigate further is that, apparently, the bank can call the HELOC at any time, meaning they may ask you to reimburse all the money they gave you at one point if they feel like it.

There are a few macroeconomic factors which could spell some trouble in the far future for Austin, but as long as building new housing stock remains difficult and there is at least a small amount of net positive migration to the area, housing prices will continue to appreciate (barring any other extenuating circumstances that are well beyond the scope of this post).

I'll second that the quit claim deed isn't a problem as long as you have title insurance to back it up.

This strategy is suppose to cut down a 30 year mortgage in approximately 7 1/2 years as long as you put more money than you spend.

(you'll still have 1250 depreciation recapture) OrYou can utilize a 1031 exchange to sell it and defer gains as long as you buy another investment

This also applies to used equipment or vehicles, as long as its new to you. 

You can locate the  office at yout house or apartment as long as you have the room that can be closed off and will not bother you with personal things to doGood luck to you!