@Susan, @Jelena, I only wish I had an easy answer to the problem, but it pretty much goes with categories in this situation.
Having something on the category page will help going forward, (not with the existing ones of course), it doesn't need to be much, something like " This category is for migration from xxxx to xxxx, during the period from < year > to < year >". Now with the WT browser extension, it's easier to look at a category page before adding to a profile.
The other thing, I noticed earlier there is a significant number of profiles in the "Country, Emigrants" categories, like "German Confederation, Emigrants" and "Holy Roman Empire, Emigrants". These are level 2, top level, and shouldn't have profiles. Same as the level 3 "Admin entity, Emigrants" shouldn't have profiles. Level 5, "Migrants from .....to....." is the best, but if only the arrival admin entity is known, then a level 4 can be used like "Victoria, Immigrants from German Confederation" or "Texas, Immigrants from Holy Roman Empire" etc.
I'm happy to help create some lower level migration categories if needed, to move some of the profiles out of the higher levels.