Will CTCSS/DCS be allowed?
Yes. Question will be if most CB users will be able to understand it, and will the CB manufacturers market them as "Privacy Codes" like they did on FRS/GMRS...
§ 95.977 CBRS tone transmissions.
In addition to the tones permitted under
§ 95.377, CBRS transmitter types may be designed to transmit brief tones to indicate the beginning or end of a transmission.
If you follow the link to 95.377, which covers all the Part 95 services:
§ 95.377 Tones and signals.
Personal Radio Service stations that transmit voice emissions may also transmit audible or subaudible tones or other signals for the purpose of selective calling and/or receiver squelch activation. These tones and signals are ancillary to voice communications and are considered to be included within the voice emission types, e.g., A3E, F3E, and G3E.
(a) Tones that are audible (having a frequency higher than 300 Hertz), must last no longer than 15 seconds at one time.
(b) Tones that are subaudible (having a frequency of 300 Hertz or less), may be transmitted continuously during a communication session.
And, by the way, the CB rules have been updated to show FM is allowed.