Not too sure how much I can actually help you, but I'll give it a try.
1) I'd wait until you have solved your other problems first before looking into this. IE: Make sure you can connect first.
2) Well, you CAN patch your files locally/off line if you download the appropriate patch and the program to do it. They're both located at: http://neverwintervault.org/
Look in the upper right hand corner and hit the, "Patches" button. Once there, you can choose NWN2 from the drop downs and your language, and OS, etc. That should narrow it down a bit for you to choose from. There will be quite a list to choose from though.
3 - 4) I would also wait on these to see if they're cleared up after your patched to the correct version as well.
Honestly though, I think it would be better to just go to GOG.com and get their, "Complete NWN2 Version" for $20. That should contain all the latest patches and you should be able to connect up to Trinity then. On thing though if you do that, you may need your old CD Keys if you have them as I believe your old characters are tied to them. So please keep that in mind.
Sorry I can't be more help, but I do use Windows 10, and I went and bought the, "NWN2 Complete" version from GOG.com rather than mess with all of the offline updating and looking for manuals and disks and such.
Good luck to you either way, and I hope this helps in some small way.