I think many of our old members will be happy to team up with newcomers to help with adapting in to league rules.
I believe that there are many formidable PvP players playing in GM or MLD format and they just need few basic tips to enter and shine in our league as well.
I'm a Zon player so if that help you, I can show your my TvT Zon on stream and explain the item setups I use for certain match up.
Regarding mana and mana pots banned. You need to stack mana in your setups as well. If you go with your no mana GM character, you will run out of mana instantly.
Most of caster characters use life/mana sc's and stack both life and mana in their circlet/amu/rings.
Remember that your paladin teammates can always provide you with meditation aura ;-)
The idea of Clan League is:
Join the clan or form one -> create your team -> train with them -> demolish other team and claim fame and respect

Some of interesting team comp. for 2v2 in current meta are: Blizz + Trap Sin, Blizz + Ele Dru, Ama + Ham, Ama + Nec, FB + Barb, Foh + Barb, Foh + FB, Nec + Ele Dru, Smiter + Barb, Ele Dru + Trap Sin