Well, yes, you can, but there is a downside.
The individual tracks may tend to step on each other, same as if you run two guitars into one amp.
Busses are good for an effect that you want to apply broadly, such as reverb or compression.
I would keep an amp sim dedicated to a single instrument.
Unless you are running into CPU or RAM issues, having multiple amp sims in use should not be a problem.
ps. When does Ace Stokes 2.5 expect to be released?