G'day Kezardin
I've definitely had my own fair share of this paranoia...
I'd go for option A). Mask of the Betrayer contains it's own set of updates in the package. (Mine got me to about 1.20, IIRC)
Due to my decidedly slow internet connection, I also had to go for the patching offline option when doing an install of NWN2 and both expansions recently. This was after I'd encountered game stopping bugs in the OC towards the end after excitedly installing MotB straight after buying it and then playing on without further patching. (All entirely my fault!) Had to do a clean installation after this.
I only ever experienced another problem when I tried to continue patching offline without grabbing that whopping 330 meg vofix update. The autoupdater would stop half way and tell me a file was missing. I solved this by getting a friend with better internet to grab that one for me, patching, then auto-updating the rest to current 1.22 glory. No issues encountered as yet though I may have rolled a 1 for initiative there...still turning over party ideas for Storm of Zehir!
Good luck conquering the paranoia Kezardin! (When in doubt, research more forums and read other stories too, they're always an invaluable source.)
Here's a handy link for anyone looking for the patches, all set out neatly in sequential order. (Though I think a link or two may be broken towards the end)
http://nwvault.ign.com/View.php?view....Detail&id=230
Edit: Whey, Edwin and Safiya be praised! I've been allowed into the power-hungry society of Thay.