Former Bolton and Oldrangers player Wylde, who can also play at full-back, has signed a three-year deal with the club.
As Aberdeen Mad revealed three weeks ago, the 22-year-old will join up with former Scotland U21 team mates Ryan Jack and Peter Pawlett at Pittodrie.
And 17-year-old Queens Park prospect Shankland, who can play on the wing or as a striker, has signed a two-year contract at Pittodrie.
New Dons boss Derek McInnes told RedWeb: "Gregg is a player will give us real pace and good balance, which is something I felt the team needed.
"He is a young player who has had a couple of frustrating years with injuries and not playing first team football but he is a player with great ability and is someone who I am sure will be hugely beneficial to the team. I'm really looking forward to working with him and continuing his development."
"I'm delighted to have secured Lawrence," continues McInnes. "He scored a lot of goals for Queens Park last season and we feel he is an excellent acquisition for the Club.
"Lawrence is definitely one for the future with the potential we see in him. He has shown a great deal of maturity to score as many goals as he did last season in the Third Division and by working closely with Neil Cooper, myself and Tony he will only continue to improve.
"It is important as a club that we continue to monitor the lower leagues as there is a lot potential there and it is important to give these players the opportunity to progress from these lower divisions."