I noticed Dave motors or large scale rc dosen't stock the torque Dom for the FG anymore, only the Torque Dom for the MT5 monster truck/monster beetle. Will this one fit the marder/baja without any problems?

i think they would fit

I know it will bolt right up, but being made for another type FG, that only means the shape may effect the body a bit, because all these FG's use the same chassis, they only differ from a few small parts like shock towers, shocks, bodies and mounts.
It will work 100%, but you may or may not need to trim the baja body just a bit, but nothing too noticeable I think

The tip to the MT Dom seems straight and a little longer, the regular marder/baja Dom seems to have a slight curve to the tip.