To fix the wobble, get a ceiling fan blade balancing kit. We used one on a fan years ago & it totally fixed the wobble. Any of the big box stores will have the balancing kits--look in the fan dept. There will be a display with various fan repair items like new switches, pull chains, balancing kits.... Should cost <$5.

(The pull chains may be causing the ticking noise.)

As to the gap, I would use some caulk backer rod in the worst of the gap & just caulk it. You can make backer rod out of most any type of foam--pool noodles, packaging foam, foam insulation board....

If you're more ambitious, the ceiling can be leveled out by floating drywall mud and feathering it out. But I'm not keen on drywall work & sure not keen on overhead drywall work. Then you gotta' worry about matching textures, etc. plus having to repaint. Caulking would be good enuff in my world. Use a paintable caulk (I like Big Stretch) and touch up the caulk with ceiling paint if you have some leftover from when the ceiling was last painted.

I would tackle the wobble by trying to level the base. Not sure what you mean by medallion, but I'd try some simple material to use as a shim first, to see if it will do the trick. From your photo, it looks like you need to shim the left side. I often use folded thin cardboard (like from a cereal box) to get the thickness I'll need. Once the shim is in place, test the fan again. If that does the trick for stopping the wobble and ticking noise, then you can change out the cardboard for a more visually pleasing fix. :)