Hi..
To start with .... Welcome to the forum
You will find a lot of good people here
regardless if about CB,freeband,FRS,GMRS,MURS or Ham radio
Here in USA..CB is used in both AM and SSB modes
(there are many radios that can use other modes)
Here in USA CB frequencys are between 26,965 and 27,405 Mhz
there is zero indication any time soon that these frequencys will be expanded..and no way they would "move" the frequencys to elsewhere
SSB is a mode of usage which enambles higher PEP power because it is using basiclly 1/3 rd the bandwidth of say AM/FM and yes i would say is better to have a CB that has the abilities to use both AM and SSB
many features can be had
is doubtfull any under a $100 are worth talking about
elsewhere on the board you can look to see what suits your needs and desires...i would say be sure you get SSB
scan is not a "typical" cb feature
most likly so it can not be called a scanner and cause issues with police and scanners in a car
using mike to do channel up or down is a ok feature
again elsewhere on forum will guide you on that
(as to what CBs would have that)
you are using a single post to try to answer a many questions
in several areas...
is rather hard to do so..
but if you look under CB section....you likly will find most of what you want..
Good luck and again
welcome to the forum