using non real players

hi if i where to use none real players what stuff would change i mean for example say van persie became watson would he have the same same attributes or would they change. Would man utd stay as a top team or could they become a relagation team?

In my experience, the names of players change, but in general their attributes are similar if not the same. So while there wouldn't be a Van Persie at Arsenal, there would be a very good Dutch newgen striker. The only real advantage to this is if you are playing a LLM game, you will no longer be able to search up players you know are good at a BSS/BSN level and are not on contracts. Apart from that clubs remain pretty similar to their squads in real life.

So while there wouldn't be a Van Persie at Arsenal, there would be a very good Dutch newgen striker.

The players nationalities do change so can be good if your starting as an international manager but nothing else really changes, even the relationships stay the same so it is far too easy to tell who the players used to be, needs to be totally random in future versions in my opinion

Clubs are given squads based on their reputation. So Man Utd would start with one of the best squads in the Premier League every time, and Swansea always with one of the worst.