It is true that some tube CD players just contain a tube buffer stage. A buffer is an additional circuit that the signal passes through that has no gain or amplification. If that is the case, then adding a separate tube buffer will accomplish the same thing, but requires more interconnects which will also affect the end result. IMHO, if adding a tube buffer results in a more pleasing sound, it's just masking a synergy problem somewhere else in the system.
As far as the Ayon CD-07, it appears that this is not a CD player with an added tube buffer. Their description of the player states Class A tube output stage and no buffers are used in the signal path.
I also agree with Charles1dad's comments, and both of these are excellent players. Provided there is good synergy in the rest of the system, either player should sound good, although likely a little different. My experience with another Ayre player and reviews of the CX-7 is that the sound is not anything close to being laid back. So, if your system is somewhat laid back, the Ayre could definitely add more of a lively sound, however, in another system, as in my experience, it may not suit someone's personal preference.