Who to level up?

I could use some advice about who to lvl up.

1.Jaden for elemental deck.

2.Yami marik for lord poison to play plant deck.

3.Mokuba for 2nd "ancient rules" and dragon support.

The 3 above are around the lvl 25 mark atm.

Any advice?

Several other chars are at 30-35 (tea, mako, ish, mai). A couple at 40 (yami yugi, pega).
Many other at 20 and below.

Who would you recommend to lvl first out of the first 3? Or some other first than those 3?
Keeping future incomming events in mind like Vellian crowler.

Can someone tell me if plant deck is any good without lord poison?


Thanks in advance.