Summary

From #29072. bar() supports

• color : color or list of color
• edgecolor : color or list of color
• facecolor: color

i.e.

• facecolor cannot take a sequence
• there are no plural aliase (e.g. edgecolors)
• likely (t.b.c.) the aliases also do not support sequences, similar to [ENH]: Expand hist() signature to support aliases and plural kwargs #28884

Proposed fix

Make facecolor accept sequences and check that the parameter precedence among color, edgecolor and facecolor is reasonable and comparable with scatter, which can take an explicit color via c (equivalent to color here).

For now, I'd refrain from introducing plural aliase. bar() is originally and primarily a style-all-bars-identical function. Per-bar styling was added later on, and I don't think there's a strong need to support this additional use case with an added plural alias.