Should there be washers (normal and/or spring?) on the bolts and nuts from the tailshaft rear yoke to the front of the diff? Or just plain nuts and bolts and some loctite?

I just did an auto to manual conversion last week, and if IIRC, I don't recall seeing any washers - I think the bolts and nuts already had a washer type face (correct me if I'm wrong). The shop manual says replace the bolts, but it's been posted you can use them again, an experienced auto mechanic mate advises the same.
A thread locker isn't necessary I've been told, but I used one as I figured it couldn't hurt (being a rotating part). I used Loctite 262.

EDIT: Remember to mark the tailshaft and diff flange to reassemble both together in the same position.

no washers are needed

but f**k man use some GOOD Locktite
and do em f**k tight u really dont want them coming loose

Yep - loctite them in and make them nice and tight

specs are 75NM but I doubt youll get a torque wrench onto them

Cool cheers.
Yeah when I first installed this gearbox years ago didn't loctite them, was driving home one night wondering what the vibration was lol! all the bolts had come loose, and the nuts had unwound almost enough that the tailshaft was ready to drop.