You definitely can get in trouble for paying people for installing the client and generating an address. Been there before.
Incentivizing people to post insubstantial posts can get you banned, paying them to generate addresses without posting those addresses on the forum is OK.
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
You also shouldn't be encouraging people to send unsolicited PMs spamming your altcoin.
Other than that, I don't really see a problem. If you're not sure you can always ask.