It has always been my understanding, when a Queen is lost for what ever reason and the workers start any number of "Queen" cells, they do not consider themselves Queen less. There fore any attempt to introduce a new Queen will fail. they will Kill any intruder.
I have also experienced this understanding.
This is a good time to use that excluder.
Take a bottom board and put a deep box with drawn comb, put the excluder on, then put an empty box on that.
Take the boxes from the hive you want to check one by one, fume board those one at the time.
The workers (most of them) will go through the excluder.
Yes, it is time consuming, but you will find the Queen/s, if there is one.
If no Queen or eggs or uncapped larvae and no Queen cells, then re Queen.
on the other hand if you find capped Queen or beginning Queen cells, if you want to put in a new Queen then all these Cells has to be removed. Then wait 5 days and check again, when there is no more eggs to make Queen cells from then you can put a "caged" Queen in.
Or you can do it this way.
If you suspect the colony is Queen less, wait at least 14 days or longer and check for eggs and or brood.
The only draw back to this is laying workers developing.
I left one Queen less for 42 days once and they gladly accepted the new Queen.
This was not taken from any publication, it's from doak's bee yard.
I know what kind of feed back to expect, so have at it.