For satellite, FBC tuner does not need specific LNB. FBC satellite tuner will work with universal/standard/normal LNB. Yes, a unicable LNB offers more options.
All the frequencies come down the same wire for DVB-C. There is no separate/special wire. I am pretty sure Oscam can only decrypt 7 services simultaneously. I may be wrong. The access to 8 frequencies simultaneously in real life only works out to be seven.