you can't area group locusts, only GroupUnitsOfPlayer works for them
Idk what you intend to do. But when creating locust, you can put them in a group. Then you can check if that unit is in the area or not.
The event unit enter region also detects locust, you can add them to locust group easier.
I'm making 2 abilities, one will add locust to units and second will remove locust. If I need to remove locust from one unit, I coulded use this ability, but it seems that I can't do that.
Maybe there is way to pick specific units from group?
It most definitely does not. Units will have no health bars and I believe no selection circle after being un-locusted. They can be drag selected but afaik click select won't work on them.I'm not sure if removing Locust works as intended..
On Map Initialization you can create a dummy group and add all locust units one by one with "group - add unit to group" action. When you need to check locust units in area just add action:I can still select them and this is enough for me. I will use this ability in roleplay map, so people can build decorations and make the unselectable with this ability, but if someone make mistake it will be easy to fix it with removing the ability. The only problem that it will remove ability from all units so you need add ability to old units again.