Will the brighter 805s be tamed by the A5 and actually provide a nice balance of relaxed presentation and better detail?
Having owned the Signature 805's, which the new 805S shares the same tweeter, I don't think they need "tamed"; if there is a problem I would look elsewhere in the chain, just my opinion.
I would expect the MF gear to be more neutral than relaxed. As for speakers, that comes down to what you like; I am guessing the SF's to be more laid back than the B&W's.