Removing wire connectors under passenger seat?

I'm working on installing the OEM Audio Plus amplifier under the passenger seat. I took this photo:

https://imgur.com/DR03Ij7

Removing the yellow + white connector was easy enough, but I cannot for the life of my get the grey one off (why must they all use different style connections!?)

Some of the install stuff I've seen also mention REMOVING the white connector piece from the metal frame, which would absolutely make my next step of tightening a nut a lot easier... but I also cannot seem to remove this piece? It wiggles but any type of pulling does not want to peel it off... obviously don't want to force anything and break something because I'm not even sure how it's secured.

Any help with these pieces?

 

My technique is to figure out where the two connector halves will split apart. Put a thin flat blade screwdriver in between them. (I believe that’s at #1, looking at the photo).

Then figure out where the release tab or tabs are. Hopefully for this connector it’s just one tab on one side, at either location #2 or #3.

Now slightly twist the #1 screwdriver to put a little separation tension between the halves and with another small flat blade screwdriver or your finger push in on the release tab(s). Keep pressing in different areas until you find that tab. It’s not always obvious when access is so obscured. When you find it the halves will start to separate. Good luck.

 

Well, I never did eventually get it... but I managed to attach the amp with lots of fiddling of my hands and the wrench... but it's all there now!

I give up, done with that part time to move on. haha... thanks though!