Personally I'm not a big proponent of low-level medics but if you're going to go that route I can suggest a couple things:
- Skip the INT, it's not worth the XP at that level (unless you have nothing better to spend the xp on)
- Skip CRG, anecdotal evidence lately has been calling into question it's usefulness at any level
- Focus on staying alive long enough to repair
- High END to lessen damage taken from ALL sources
- High Speed to prevent non-tactic damage from landing
- AVD is still legit at your level, use it
- Decent STR for Armor (but do NOT waste XP on RNK) and to mitigate Stuns
Also what TT said about weapons.
Get a XS2 or a Saber (or whatever that 3 FRP Reaver weapon is, it ain't bad until Psych nerfs it later).
As for other classes other than medic, everything I said about staying alive still applies
... and about CRG
... and about their feeder stats
Pretty much all the same until you get up about 1 Mil XP and have a solid base, then you can start worrying about feeder stats.
Also as for alts: Just pick whatever has the cheapest xp costs as the little difference in the activation rates (if any) compared to the more expensive ones likely won't matter.
But that's all just my opinion (backed by data)
***EDIT
If you're just looking to reformat for this event then I suggest making 5 Characters that ONLY care about their specific tactic (ie no dual tactics unless it's avoid) so that they don't waste time doing whatever the other tactic is when they could be getting you points.
There's also probably something to be said for having just and average weapon in the cases of the characters that need to kill opponents via a tactic so that you don't accidentally kill them via weapon.