1. Yep, regular usb1.1 ports
2. Could but haven't found a decent use for it
3. Why not make your own?…..takes about 20 minutes with a soldering iron
4. Yes they are but since you can still manage vi the RS232 port this is more for convienence
5. I've used a k6-2 380 oc'd to 400 w/out a problem
6. Good luck with the bios flashing, didn't find anything decent
7. Yep
8. Some of the dip switches set the RS232 configuration while other sequences offer a similar function to holding certain keys on a keyboard down while it boots to reset the device's configuration while it is running the OS from Nortel.
BTW, this has been discussed awhile ago on the FAQ's: http://faq.pfsense.org/index.php?action=artikel&cat=2&id=27&artlang=en&highlight=contivity
Also, if you look around online there's a thread somewhere if you lookup the motherboard model you'll find some more information that has come across over the years.
My only gripe with the series is that there is no real mention between the different models.....ie the "contivity 100" has been around for over 10 years with many different hardware configurations but yet they still keep the same model number....the only key for use with pfsense is any of the original "Bay Networks" variants are too old for use as they had a soldered on AMD 486 series CPU. I haven't seen any 1st generation Nortel branded ones but from what I have seen the hardware seems to work pretty well for at home or in a small office....in a larger setup the CPU tends to be the limiting factor when you want to setup site-to-site VPN links.
Your best bet for bios flashing would be to extract the current bios and see what features are disabled on the current bios and then attempt to reload it later.