The top one looks like a spot for a pistol and possibly an extra magazine.

The bottom one looks like hooks for grocery bags, gotta keep them beans from falling out tha sack.

 

The bottom ones are definitely grocery bag hooks. Not sure what the top one is.

 

A place to put your extra AR-15 BCG.

 

Top one is known as a crap catcher. lol Seriously, IDK...what's under it? Perhaps whatever is under is the reason for the odd shape.

 

Ahhh...grocery bag holders...love it.

The armrest thing may be the profile of the seatbelt mechanism inside the middle seat now that you mention it. It is a pretty useless part of the storage under the armrest, I suppose you could put change in there, it would be trapped in there once the top is closed.

 

glock storage