They are a fantastic group of talented singers and I hope they do well!
Apparently 放課後ハイファイブ peaked at 12 on the Daily Oricon and 18 on the Weekly - not sure how significant that is, but it seems decent for a debut single.
Second single and tour info:
And yes, Karen, I think you girls should be on Kouhaku 2015 to blow everyone away, so go for it!