Hi, in regards to list names you have hit upon a problem that I tired to raise also in connection with the Common Data Model which seems to have the same flaws even though the Microsoft team insist they are not related.
Anyway back to SharePoint lists. Each list in SP has an internal name, which never changes, and a display name that you can change. So say you create a list called "MyList", and you look at its URL you will see that it says MyList somewhere. You then change its name to MyAnything and its URL will still contain MyList. Now here comes the relevant bit. When you delete this list and create a new one also called MyList then you will see from the URL that the internal name of this new list will be something like "MyList1" because the internal name remains reserved even though the list has been deleted. I am not sure if by purging the list from all rubbish bins will clear the reservation/cache, but I don't think so.
This explains part of the problem but does not solve it. I am not sure if PowerApps refer to the internal name or the display name of the list when connecting (I use Azure DB as a source generally), but you can experiment and find out. If it is the internal name, then you should look for that in the list of sources available for your site.
In regards to deleted Apps please see this: https://powerusers.microsoft.com/t5/PowerApps-Forum/Keeping-Things-Tidy/m-p/5292/highlight/true#M2411
If you are interested in CDM and its flaws, my comments are here: https://powerapps.microsoft.com/en-us/blog/cdm-preview-available-for-powerapps/#comment-2828077868
In actual fact when deleting an custom entity in CDM (basically a list) and recreating another with the same name, you actually get back the data in the Title field as well! This is even wierder behaviour.
