not really. If they would concentrate on foreigners only, they would not make enough money. The rates may be slightly different, but they also prey on Thai drivers.
Harleys start at price of 1 mio Baht in Thialand. Get used to smaller bikes, if you just want to go around your home town or provice. 150 cc machines are fine.
No, you do NOT need a foreign Motorcycle Licence, but then you will have to sit for the test and have a test ride with the officer looking. But that is also quite simple and nothing to be scared about, if you have a little experience upfront.
If you have a foreign licence, than the test and test ride are not needed.
Before you transfer money to buy a house or condo, please inform yourself about the conditions for doing this. There are certain steps to follow, and how to transfer money to Thailand one of them.