The machines you listed would be fine for trail, however, they would be boat anchors off trail.
As has been stated, i would get 2 machines.
I would go for a min of 700cc (depending on how much you want to spend).
By using 2 machines you can each ride your own in. Then once there you can "shuttle" up and down the hill.
Leave one machine at the bottom.
Double up, ride to the top.
One boards down, the other rides the sled.
Then switch.
Or, if you are one shotting the hill. leave the 2nd sled at the top, you both board down them double up on the sled at the bottom of the hill to go get the sled at the top of the hill. Repeat as you like.
The other part of the reason you want 2 machines is in case one breaks down you can tow it out with the second or go get help.
Be warned.
I have said this to a number of people and none believe me at first.
You will find yourselves using the snowmobiles more and more and the boards less and less till all you do is sled.