Umm why not? If there is no front driveshaft why would it matter if the hubs are in or not? I used to drive with the hubs locked in all the time in the winter.
Avery I am not sure what the concern is with the front driveshaft, but yeah just unlock the hubs spin the yoke, and you should be able to see the axle joints at the steering knuckles spin. Lock the hubs in and try it again you shouldn't see the joints spin. If all that happens then the front end is fine. I imagine the front shaft is removed to due length or angle issues with 9" of lift.
You don't
need a gasket for the diffs if you change the fluid. I would bet 90% of the members here use RTV. Actually there was a poll on it within the last 6 months. Clean up both surfaces and RTV it up. Never used a gasket on the diffs before, but just my opinion
As for the oil dipstick. As mentioned some of them pull out easily. I believe there should be an O-ring where it goes into the pan. Check that for leaks.
Get the TV cable adjusted ASAP. That will kill a 700R4 fast if adjusted incorrectly.