They wouldn't put him in Bayonetta 3 just to put him in Smash
There's alot of potential factors. Like I suggested in one of the Bayonetta 3 X Shadow Topics, Nintendo and Platnium would get more money by Putting in Shadow in Bayonetta 3. Sonic fans would be more interested, and there' definitly be alot of Attention on it since It be the 2nd Coming of Shadow using Guns
Sega will get more Shine on Shadow. they've been pushing him harder these days compared to the Early 2010's, where like most of the Sonic Characters not named Sonic, Eggman, or Tails, he was barely used. It also could be the Blueprint for a Sequel to Shadow the Hedgehog as an action game. from there they can actually create a New Franchise based around Shadow, for the more mature fans and stuff
Even if Bayonetta 3 Theory doesn't happen, I still will think Shadow will be in fighter Pass 2, Unless something happens that i have to give up on Him being in this Fighter Pass
But I'm not trying to suggest Bayonetta 3 would be the Sole Reason or main reason. it would be the Cherry on top that could Benefit Nintendo, Platinum, and Sega all at once.
If I did do this, Should I Make it a Ship?