Hey @Jaki87,
I would evolve Onix and Roselia, you'll be more powerful!
For Onix, you need to hold a metal coat and to trade with another player. You can ask Staff to help you from our PRO Discord or you can also ask here!
For Roselia, you just need to use a Shiny Stone. You can find one in Kanto Safari Area 1, on the Eastside of the map, a NPC is a bit hidden under the trees! It will cost 20k.
Gengar would be a nice addition to your team anyway
Here is a Leveling Guide
Don't hesitate to bump this thread if you still got difficulties.
Have a nice day and good hunts!
Lughus