Let's see, the actual KS is for Clan Invasion Box Set with at least Timber Wolf, and 4 others.
Stretch goals include "lance packs":
Clan Command Star: Dire Wolf, Shadow Cat, Mist Lynx, Stormcrow, Summoner
Clan Attack Star: Warhawk, Nova Cat, and 3 others
These add up to at least 6 of the original 16. At least 2 outside of the original 16 are included.
IS Command Lance: Marauder, Archer, Valkyrie, Stinger
IS Battle Lance: Warhammer, Phoenix Hawk, and 2 others
Missing Classics, after adding up the beginner box, AGOAC and the KS lance packs:
Rifleman, Wasp, Crusader.
I'd assume there will be at least third "lance pack" stretch goal for each side, possibly more.
I would expect we'll see all Classics for the Inner Sphere, along with some remodeled ones (personally wishing for Raven, Atlas, Cataphract, and JagerMech).
For the Clans, all original 16 is possible but is it probable? Personally i've huge issue with incomplete sets, and the original 16 form a set.
As for Clan 'Mechs beyond the original 16, which ones are popular? The Shadow Cat and Nova Cat are as far i can determine, probably one reason they've been chosen to the "lance packs".