Davis will join the Bills' Mafia to begin his professional career after scoring 261 points in three seasons as a Nittany Lion.
Haley will join Saquon Barkley in the Big Apple after signing on as an undrafted free agent.
A rock at offensive line for Penn State, Brendan Mahon is now off to Carolina to begin his NFL career.
Nittany Lions Saeed Blacknall and Jason Cabinda have signed deals with the Oakland Raiders after going undrafted, according to tweets from each of them.
Penn State cornerback Christian Campbell is the sixth Nittany Lion to be selected in the 2018 NFL Draft.
Allen was selected with the No. 148 overall pick in the 2018 NFL Draft and will stay in Pennsylvania.