For the first game, I recommend the solo game (not Solo challenge) to make sure you have the rules down absolutely flat. That one is only available for the Standard version of course. A two-player game is also fine as a first game (either Standard or Classic). I do not recommend having 4 newbies play with constant rule lookups, that is a recipe for disaster.
I don't think either the Standard or Classic games are intrinsically better as a first game. It just comes down to your group's style. Ameritrashers would enjoy the standard game more, eurosnobs would enjoy the classic game more. Both are great though.
As far as number of players, if everyone in the group is fast, and at least one person has the rules down flat, then 4 players is fine even with 3 newbies. (But still budget at least an hour per newbie player + 30 minutes for setup/takedown.)
On the other hand, if anybody in the group is prone to analysis paralysis, even 3 players may be painful if everyone is new, or if there are frequent rules look-ups. It is absolutely critical to minimize downtime in this game. Play solo or with 2 for as long as you feel you need to look up rules. Fortunately, I think the game plays fine with 2 (or with the Solo challenge).