How many cameos do you think Stan Lee pre-recorded before his death?
Three. In theory, we should see his cameos in Captain MARVEL, Avengers: 4 and Spider-Man: Far From Home.
He was known to fly out and then record multiple cameos in one shooting (normally aimed to be completed within one day as well).
Thinking about it, I think MARVEL may look to CGI Stan Lee into future films. The CGI of Paul Walker in Fast and Furious 7 was exceptionally good, albeit for a small scene/role, but then Stan Lee never had a huge role in the films either. Some people may take it to offence, because his legacy shouldn't be altered bla bla bla, but I think a lot of MARVEL fans would appreciate it and it's the least the company could do for him.