There should be ample amount of room in the 900 engine compartment to get all of the bolts off. Removing the distributor is a big help because it gets it out of the way of what you're doing. I've traditionally just used a socket on a big 1/2 breaker bar, but my breaker bar pivots a little more than most. I'm trying to remember removing a 700/900 series AW transmission, but for the life of me I can't remember running into any problems doing it; I could be missing something.

When removing the crankshaft sensor, make sure not to break the sensor bracket. Ditto for when you reinstall the transmission especially, since the bracket breaks easily. Never force the crankshaft sensor. To remove, you can rotate it gently in the bracket and it should come out.