yes there's a looooot of other ES units! starpro for example has a LOT of newbie idols, and akatsuki, undead, and ra*bits all faced seniority issues with other rhythlin idols that have been there far before they entered the agency.

there are girl idols too; as hinted to by in Parallel World and confirmed in Matrix, there are girl idols within ES, but they are treated unfairly and given little to no recognition. we don't know the specifics such as "all-girl", but it seems to be implied since ES typically deals with units.