Alex Wesker is the primary antagonist of Resident Evil: Revelations 2 and has been referenced multiple times in the franchise. Alex was taken from her parents and was put into the Wesker eugenics project, just like Albert Wesker. She is also known to be batshit crazy like her 'brother'.
Ozwell E. Spencer was one of the founders of Umbrella Corp. and owner of the Spencer mansion that served as the centerpiece of the original Resident Evil. He featured in Resident Evil 5 where Albert Wesker murders him before setting the stage to enslave Resident Evil 3‘s Jill Valentine.
Capcom has confirmed that Resistance isn't actually canon, meaning these two Masterminds who are seemingly dead, can still take part.
Two new maps have been confirmed as an addition to the game; Casino and Abandoned Park. Screenshots are found below.
Resident Evil: Resistance and Resident Evil 3 will be available on PS4, Xbox One and Windows PC from April 3, 2020.