Hey,

If i have this charmander and wants to reset the game and start over again, will i be able to trade that charmander back to the newly restarted game from another 4gen game? I dont need national dex to get the charmander as a "starter" will i?

Yes, you will, just won't have Pokédex entry.

I'd like to point out that unless you have someone with a ds that you trust, you will not get charmander until the first badge is gotten (wfc is still under repair until then).