Buy and hold in Austin Tx 78744 and 78745

[Travis Evans]

hello, my name is Travis Evans. I am looking for information on these areas above. I own SFH in 78748 and rent two rooms for $700 apiece, and keep the top floor for myself. The home is worth 280k and I owe 108k, I am looking to borrow 50k against the equity to purchase my next property/s and do any rentavations necessary. I have many questions.

1: how much of a tax discount do I receive from my homestead exemption?

2: If I "reside" in the next property can I purchase at 5% down instead of the 20% for an investment. 

3: is 1% of the home value on average and depending on the area the price I should charge for rent?

4: anything I missed "a lot I am sure" feel free to add...

Thanks in advance 

Travis Evans