It looks like you have some aftermarket universal ICE motor mounts. Rather than use these, maybe a simpler way to mount the front of the transmission to the frame, is to use the existing angled frame mounts either side of the bell housing. You could make a simple, one piece flat plate cross member that picks up at least 2 of the transmission face bolts. Or, a 2 piece, flat plate mount (one on each side of the bell housing) that picks up at least 2 bolts each side. These mount(s) could be attached to forward extending flat bar pieces bolted to the existing angled frame mounts. You should include some gusseting where the plate(s) and bars meet, for additional strength.
My plan is to have 2 torque bars that run back from the motor mounts and bolt to the adapter plate (where the 2 bolts are inserted in the image). The motor will then rest in a cradle that spans between the torque bars.
Even if you wanted to include some anti-vibration rubber elements in this alternative design, it probably would be less work and a cleaner build than trying to use the ICE motor mounts.
I'm not quite sure what you mean by resting the motor in a cradle. The motor has a very stout face mount that is designed to support the weight and torque of the motor. I'm assuming the CANEV adapter plate is likewise stout enough.