baby Murraya Paniculata in need of help

Hello Forum!
I'm a total beginner in the world of bonsai, (despite the facts that I've read almost everything there is to know on the internet) but a few days ago I found this baby plant and just had to save it from the cruel treatment of the flower shop. It is in desperate need of repotting, the roots are sticking out of the draining holes, and I would also like to style it, but HOW? Where do I start!?
Is it too small to be wired? Will the trunks fuse together as it grows older or is it possible to slit these up in different pots? Can I pinch/prune the other trunks off or will this hurt the whole plant?

In need of help!
Linnea and Murraya
(from a cold Sweden)