The pictures should not be hung into the border.

I agree, if you feel you want to hang a few photos, go with a smaller set of three above the border.

Have the pictures bottoms come no closer than 3" to your border. Hopefully, this puts them at eye level when you're standing.

You cannot expect a designer-look with that border and a picture partially covering it. Choose one or the other. The basic rule for height of hanging art/photographs is eye-level as seen from the center of the room. That may also help in your decision.

There seems no rationale for installing a border at the height you selected. I suggest you remove it as it really dates the room.

AND, there are no rules to border rationale;)

Respect the border patrol!