1. I'm not sure if you can restrict trickplay to a section of the file. Most apps that use this feature disable FF/REW. It would probably be better if seeking were restricted to the range specified. I'll file an enhancement request for this.
2. You don't have to do anything special, although remember that you can only seek to an I-frame. If you have certain critical seek points you should make sure that they each line up with an I-frame.
3. There will be buffering between the segments. There's no way to avoid this other than to encode the content as one stream.
--Mark