As far as I'm aware you should be able to use all of the original clothing etc.

I don't use Poser much if at all really so I don't know if the Poser version of SR1 is different but in DS I haven't had trouble with anything.

All the Hivewire stuff does work I know.

As to problems with logging into Hivewire, try contacting Alisa over there if you can't I can direct her here for you and she'll sort out your problems.