Ok, here's the skinny. There are certain things that you agree to, depending on the program, regarding the length of time you commit to living in a property. Normally, the down payment assistance comes coupled with an FHA Insured 1st Mortgage at 97% (ish). Programs like MFA grant (lend) the difference and only require you come up with 1/2 of 1% - Usually your earnest money. - You may have committed to as little as 6 months or up to 5 years. If you sell or rent the property prior to the time set out in the agreement, they can penalize you. That's not necessarily the answer to your question but it lays the foundation. Follow me...
Non owner occupied properties (houses you don't plan to live in) RARELY qualify for these types of grants. HERO type programs are designed to increase home ownership for public servants by making it easier to qualify. For clarity, home ownership in this example is the home you live in.
Now, that doesn't mean that you cant go out and buy another property with a conventional mortgage. However, lending institutions usually require 20% down on these types of loans.
On to my personal opinions ;) - The market is stronger than it has been since 2008. Last month, home sales were up 15% from March 2014 and Inventory was down 17% - Wherever or however you're planning to force appreciation... do it now! The market may continue at this current uptick but with a big election right around the corner you're guaranteed to see some market correction; interest rate increases, REO Inventory, etc. - You can quote me on this ;) The old school standard of 3% appreciation year over year is gone and if you don't think that 3% gets eaten up by at Quadrillion Dollar national debt, well you're just not thinking it through.
The End -
P.S. I hope that helps! Reach out to a lender for further clarification. A lot of new financing depends on your ability to qualify.