[quote=@Marayla]
<Snipped quote by Zarkun>

In the novels I've read, it seems to be all ghosts that have it.
In regard to serial numbers, there's
Agent X81505M,
Delta Emblock a.k.a Agent X10128B,
November Annabella "Nova" Terra, a.k.a. Agent X41822N,
Kath Toom a.k.a. Agent X52735N
etc.
My point is, they seem to all start with 'X,' have another letter at the end, and have numbers in-between.  They also all seem to be 7 digits.
[/quote]

I do not believe all Ghosts have the influence mind ability. Telepathy itself, yes, but influence mind no. It is however a more common ability.
Ghost serial numbers consist of a letter, a five digit number, and another letter. Such as those you provide examples of. In Zarkun's case, he can have two letters before the five digit number if he likes since he's kindof an experimental ghost.