Would it be a totally bad idea to add solokill and partykill plaques somewhere
(in adventurers guild maybe?) Just thought it would be nice to see how i
compare within other players.

Yeah, except many solokills are assisted by someone else.
Either by active prot/heal or by somebody first kicking
the mob to nd and then someone goes to finish it with wands or
something. In order to get that plaque working, there should
be a mode in which you 'perform' your solo-kill.
Like you set solo-kill yes, and after that you must not
receive direct heals, and the mob you're fighting must be exe when you
set the variable, or something like that.

~/A