Comments below based on the Verizon DSL service, probably applicable to FIOS as well but no warranties, express or implied [etc] ...
Obviously (I hope) not *every* USENET newsgroup is carried, but they seem to carry most of the ngs that aren't blatantly illegal. No limitations on usage.
I last connected to MSN while working on the technical beta for Windows 95, and then only as part of the beta...and I have absolutely no intention of ever doing so again. In other words, yes.
You get one IP per account, and using only one IP at a time is part of your TOS. You are explicitly permitted to connect any number of machines to Verizon through that single IP address using a NAT device.
Gray area. The TOS forbids both business and personal servers, but there seems to be some wiggle room based on interpretations by some of Verizon's comments. I've not needed to look into this so I'm not speaking from experience.
Reportedly yes but not at present (other than some possible testbed areas) AFAIK.
The price will be lower if you get it as part of a package with local landline service. My *guess* about the nonlinear price structure is that the provisioning of the residential lines is set up with the assumption that most users won't have any nonbusiness need for anything above 15, so the additional work and equipment required to support a line at 30/5 justifies a premium price. Also, by the time you're using 30 MB/sec it's not unreasonable for VZ to wonder if the customer is trying to run a business interface on a residential circuit.
Can't say ... but if the 199.95 figure is for *business* service then I would expect no restriction on running a server.
I don't know what specific fiber they're using, but 15 MB/sec is unlikely to be more than a small fraction of its potential.
Joe Morris