An interesting question, but I think you are slightly confused.

Re-x = recrystallise. This is usually a purification step in itself. And as far as I'm aware there aren't really any other alkaloids pulled from mimosa using the methods we do on here,  the high nn-DMT content and low plant fats/oils is also the reason why it is the popular choice of starting material.

If you were to evaporate the solvent left behid after a freeze precipitation you would most likely be left with a very small amount of DMT that failed to precipitate in the freezer, some plant fats/oils and possibly some basic soup brought over.

The presence of any other alkaloids besides DMT would be so miniscule as to be unnoticable.