The thing you could and definitely should practice on your current bike is the track stand, it's the key to all other moves.
With regards to bikes, in my opinion most trials bikes aimed at pure trials are still good for street, but the higher end frames have a potential to snap if you bash it a lot. 24 inch frames like the zoot and inspired are good for Danny mac style street but a beginner will find hopping on the back wheel hard compared to a high bb short chain stay frame.
If I was you I would go with one of the echo full builds, they are cheap for what you get and are still strong.
Don't be shy from ordering from tartys either, there reputation is second to none, and the staff are very helpful too.