If you played Star Fox Command you would see how important Krystal is, probably more than half of the story lines in that game was pretty much about her
Star Fox Command is also a pretty terrible game, but regardless of that fact, I wouldn't mind Krystal in a Smash Bros game. Although I generally don't like characters getting cut, Wolf IMO is more unique than Falco in terms of moveset and playstyle (when compared to Fox, anyways), and I would've cut Falco for Krystal instead of Wolf if it had to come to that.
Chrom is a solid choice, given Awakening's success, though I could easily see Lucina or both of them as a duo character in that spot.
Lolo+Lala is interesting to say the least. I would actually put Lucario in this over Lolo+Lala. You already have Captain Rainbow, who is a much more interesting choice. But that's just me.
As for Black Shadow, I find Goroh to be more interesting for an F-Zero rep. Who doesn't love a fat samurai who can do backflips? Again, that's just me.
I honestly don't see Snake nor Sonic returning, as much as I love them. They had their moment to shine in Brawl, and fighting games usually never have guest characters return. Then again, Smash is not your usual fighting game, so who knows.
In the end, your roster is your roster and I guess everyone will feel differently in the end, but I would be fine if this was the end result.