They've been schedules for some time now, check the Evocommand site for a list of upcoming units.
Basically, the stinger teams are the USMC anti air, just in time for the air units coming out for EFTF and PLA.
The leopard 2 is just a really nasty tank from what I hear. Goes well with the German Heer infantry team which includes AT weapons too.
PLA sniper teams are just that, probably similar to the Fedayeen sniper model, but in a small 2-3 man team. Forward deploying and with stealth or something like it. I'm glad the PLA are getting this unit early to deal with the MEA snipers.
MEA snipers are the same, but probably more individual based, going with the whole MEA insurgent mentality. The revered leader, so I hear, is like a command model, but it can be bought and attached to individual squads to give them some extra actions or some other special ability.
Keep in mind that these are likely wave 4 or 5 at the latest, and that's well after the main rulebook comes out.