I don't believe that you will find any consensus that will say staying with one manufacturer for amp and preamp will yield optimum results. It may, it could, it is possible, but far from being a necessity. There are many manufacturers that are famous mostly for their preamps, Klyne, Aesthetix, Hovland, CJ, CAT and others. There also are many maufacturers that are famous mostly for their amps, like Plinius, McCormack, Krell, Lamm, Pass etc. There are manufacturers who are equally well know for amps and preamps, BAT, VAC, VTL, Mark Levinson, Ayre, etc.
In my 30 years in this hobby, I've found sonic nirvana with preamps and amps from the same manufacturer. I've found sonic nirvana with preamps and amps from seperate manufacturers. I've heard preamps and amps from the same manufacturer sound 'not too pleasant'. I've heard preamps and amps from different manufacturers sound 'not too pleasant'.
Bottom line, IME, you'll get some say that preamps/amps from the same manufacturer will yield optimum results. You'll also have some say that same manufacturer for preamp/amp will not yield optimum results.
So to answer your question, no, I do not think you will find a consensus that will recommend preamp/amp from the same manufacturer. You will just have to do it the old fashioned way, and listen for yourself. Then you can form the most important opinion of all.....your own.