Hi Pak,
I know this reply comes a few months after your post. I have a TC40D with 17LA front end loaded (17LA goes with the supersteer model tractor whereas 16LA goes with the non-supersteer) and 914A 84" mid-mount mower. The answer is yes, you can mount both. There is some significant hardware to mount which will stay attached to the tractor once installed. Once completed, mounting the mower on/off the tractor takes about 3-5 minutes. It's just a matter of connecting/disconnecting four pins and the PTO shaft. The hard part is installing the brackets AND the drop-down box that feeds into the cover you referenced above. Check with your dealer on price, but I know the drop down box and some of the required hardware was pricey. If you're still interested, reply to this and I will post some pictures.