You certainly have quite the amplifier stash. I wrote earlier that the Bottlehead tube products were although inexpensive they are well thought out engineered components. A price point is targeted and so the best quality parts can not be utilized.
Well, it seems that this principle is applicable to the Muzishare and Willsenton amplifiers. Good solid design with decent but not the best quality parts due to cost restraints. So very good candidates for upgrading part quality to achieve better sound. I believe that your project will turn out fine.
Charles