Marcy MWM-990 150lb Stack Home Gym

Not sure but some kind of composite does not seem like cast.

Unfortunately it does not come with a floor mat. But the gym is outstanding.

Yes, the butterfly exercise can be done on this machine. The butterfly arms can be locked to do a bench press exercise as well.

While sitting on the floor and using the lower cable, a seated row exercise can be done.

I sit on the floor in front of the machine and hook a rowing handle to the bottom pulley attachment. Or sit on an inflatable work out ball.

Add the chain when using the lower pulley to do curl or facepull. that should prevent the weight stack from topping-out.

We ordered from amazon and assembled it ourselves. I suppose you can look for sellers that will assemble it.

That is a good question, I think you would have to send the whole thing back.although I have had mine for a while now and it still works completely fine.