I think the problem here is a difference in the definition of "popularity" between you and
Shroob
.
To you, popularity is being popular
in the Smash Bros. fanbase.
To Shroob, popularity is being popular
overall, including outside of the Smash Bros. fanbase.
Looking at it from both points of view, I'm more tempted to believe we'd see Steve first. Minecraft's worldwide popularity is absolutely astonishing. As you said,
Minecraft is known by everyone. I say everyone because Minecraft is one of the few games able to achieve popularity on that level, and I'd say it even beats out Final Fantasy and
many other Smash series in terms of sales
and the popularity that stems from that.
Banjo & Kazooie will definitely be in this game though. With mass fan demand and Phil Spencer talking about it, I'm sure we'll be seeing them eventually. They might just have to wait a bit.