Do what you gotta do man. Can't wait to see my how my Zero suggestion works out. As for the Sonic Forces Mash-Ups try out Sonic Adventure 2's version of "Supporting Me" with Sonic Forces version.
Miltenacious Power: Standby~Zero (Command Mission) Reality: Theme from MvC3 or Ps1 version of his theme in X3 Mind: Determined Eyes (Megaman ZX Advent) Space: .Vs Zero theme (Megaman Network Transmission) Soul: X vs Zero theme Original (Megaman X5) Time: Cannonball Hard Revenge (MegamanZX). Use Sou-Genmu with it and just spam Hadangeki while charging his buster, then release it to unleash Rekouha. Basically just rush'em down.
