The engine in your tractor should hold are 6.5 quarts (6.2L) of 15W-40 oil. That amount should fit in most oil collection pans.
If you want to use kitty litter as oil clean up, that's a great idea. I'd suggest you get the non-clumping kind. Kitty litter does a great job of cleaning up spilled oil. It is what I use. As long as you place the pan correctly, you shouldn't spill too much, but it's always a possibility.
I see both cartridge and canister oil filters shown for the Massey Ferguson tractors. If yours has a canister that looks something like this:
Be prepared for a struggle. The rubber o-ring gasket at the top has a habit of locking the canister into position. If a regular filter wrench does not get it off, you'll need to use something like a large set of channel lock pliers or even a larger pipe wrench. I've also stuck a screwdriver through the body of them to get them to come off. It can be a lot of fun. If yours has an element style, getting them off is a lot easier.
Once the oil filter (if canister) is off, ensure the gasket has been removed with the oil filter. If not, you'll need to pull it off the engine. If it is left there, it will leak.
Double check to see if your tractor has one or two oil filters. Sucks to not have what you need.
You should be able to pull the dipstick to see the state of the oil. If it feels runny on the dipstick or you can see it drip off of there, you shouldn't have to worry about it being gelled up or cause you an issue draining it. Even if it is a bit thick, it will still most likely drain out ... it might just take a little longer.
Putting the oil drain plug back in, ensure you do not over tighten it. Stripping out the threads in the pan isn't a good thing. There's a happy medium between too loose and too tight. Get the plug to snug and give it another 10-15° of turn to get it there. Too much more than that and you can expect trouble. Also check to see if there is a copper or aluminum washer on it. Make sure it's back in place and in good enough shape to seal the plug. It's a lot easer to change it out when there's no oil in the pan rather than finding it leaking after the fact.
Once the oil change is complete, plan on changing the oil again a lot sooner than the normal oil change interval. The reason for this is, you never get all of the old oil out. Once the new oil is in and runs for a while, it'll mix with what was left. You'll want to try and get this out as well. I assume the tractor has an hour meter. Running it under normal use for a couple of hours should do you just fine. Change it again, then just do it under a normal schedule.