Now, any latecomers to the RP should have their starting levels match the current levels of the party. Right now that would be level 2, so Marcus gets 7 more points to distribute among his 4 main stats, and it has to be at least one point per stat.
I'll be basing the stats of future equipment on your characters' stats. If you have a high Strength score, for instance, you'll be getting weapons with a higher Attack score. The difference between the high and low stats will become more pronounced at higher levels.