Nomada sp. (Lower Saxony)

[Jann Wuebbenhorst]

Here are some photos of three Nomada species which I suppose to be 1. N. fucata, 2. N. bifasciata Can this be confirmed? About the third one I have no idea - maybe N. panzeri or N. albogutatta?
They are all from the same place, an abandoned sand quarry where Andrena flavipes is common (I didn't find A. gravida there yet). The photos are from 28-04-17 and 01-05-17 (Eastern part of Lower Saxony, Germany).
It's not to see on the photos, but the sterna of the supposed bifasciata are red indeed.
Are there other Nomads to be confused with fucata and bifasciata that look similar and also have only a single yellow spot on the scutellum?
best wishes, Jann