Hello Knowledgable,
"- Both side A and B of each server has RAID5 configured at the hardware level"
Do you mean the disks are RAID5'ed in a group before being presented to vSAN? (unsupported)
Or that the controller 'personality' is RAID5? (also unsupported, only RAID0 and Passthrough(HBA) are supported and which/both depending on the controller and configuration).
"What I would hopefully like to achieve, is having vSAN objects replicated between side A and B on each server (so i can lose a disk group and still be functional), as well as remote protection at the secondary site."
Normal FTT=1 with RAID1 (a PFTT=1, SFTT=0 Storage Policy in a stretched cluster) will ensure there is a data component replica at each data site. However remote protection (e.g. local FTT=1) is not possible with a 1+1+1 stretched configuration as you have here (this would require a 3+3+1 configuration at minimum).
More information on typical configurations, their FTT, FTM, % used and requirements:
http://www.yellow-bricks.com/2017/05/30/sizing-vsan-stretched-cluster/
Bob