I would just look into what it would take to get the Massey running first. Could be something simple that you could do. Get you one of these:
http://www.repairmanual.com/online/massey-ferguson-mf135-mf150-mf165-tractor-manual-mf-27/
For the use you want to get from a tractor so far, the 135 would suit your immediate needs. As you settle in and actually find your (or your wife's) niche, you can reassess your needs and get something better. It looks like the 135 has been maintained pretty well, judging by the paint on it.
Regarding the backhoe attachment, I think you can get kits that might fit on most any kind of tractor, they probably use the PTO to power an auxillary hydraulic pump. Your backhoe attachment would be in the way of using the PTO for anything anyhow if it is attached to the back of the tractor.
Since you have no experience with farm tractors, a couple things to look for/think about:
1. Most all of your smaller farm tractors are not really built for heavy duty front end loader use. Check attachment points and front end over real good for evidence of excessive wear and previous welds where cracks have been repaired.
2. Before buying any used tractor, find out where the supporting dealership is and what reputation the service department has. Wouldn't do much good to save $1,000 on the purchase if you have to drive 100 miles anytime you need a part for it, or have to mail order them.
3. Here is another source of info for tractor specs for use in comparing models:
http://www.tractordata.com/
4. Read, and heed, the safety info in your owners manual. There is no room for mistakes, especially around the PTO.
Good luck with everything!
C