Trump is involved in every aspect of his business, so it is silly to think that the donations from his Super PAC came to the attorney general without him knowing what was going on. He also made his own contributions, as did his daughter. He clearly wanted a favor in return, namely not suing his university.
Yes, Donald Trump was involved in pay to play schemes, and he still is. Trump recently paid off several people who were willing to open an investigation into Trump University. He will take any favors he receives and will give any gifts that help him rise in fame and power.
Trump is a man who will do anything he can to get his own way and his name out there and heard by the media and by the public. This involves using pay to play schemes to help him gain any kind of advantage he can during the election and to gain supporters.
The Trump Foundation was recently fined $2,500 for a blatant pay-to-play scheme in the state of Florida. The fine was levied by the Internal Revenue Service for making a donation to the Florida Attorney General Pam Bondi. There are likely other instances similar to or exactly like this one uncovered.