I'm currently supplementing fiber just because I'm doing a diet that's very low carb most of the time. If you're doing paleo then get tons of green veggies and apples as suggested and you should get plenty of fiber. Fiber supplements, however, are cheap and easy to add to a protein shake, so it's a good idea to toss a little extra in even if you aren't having issues.
As for the creatine, Just find a good deal from a reputable name. Just get monohydrate, don't worry about the fancy versions.
Bodyweight- 231, currently cutting to under 220
Raw total- 1280
Geared total- 1480
Best gym lifts, single ply-
Only goal- ELITE as soon as humanly (and chemically) possible.