Fiesta MK7 4 spekaers to 6 upgrade

I just bought new MK7 (3 doors version) with 4 speakers on font doors, rear speakers are missing. When I looked around in to the car I realize that adding 2 rear speakers will not be easy like how I thought so. With to much trouble I partly removed one rear speaker panel. I found speaker wires and place for the speaker. Speaker hole is ~17cm round type. (I could not measure correctly as I did not remove panel completely). I tested those speaker wires and it looks like that wires are not connected with head unit. Also I noted that head unit don't have font back fade option and then I realize that I am in the big trouble. Fiesta which I checked before I bought my had same head unit but with font back fade option so it looks like I made mistake as bought 4 speaker version with idea to add rear speakers my self.

Like how I can see I have 3 options:

1. to add 2 more speakers with parallel connection

2. to add small 2 channel amplifier

3. to do nothing ...

I read threads:

Installing a Sub box to Mk7

Removing Head Unit on New Mk7

and I could not get to the head unit because I am stuck after the first step. I am afraid to remove panel below as I don't know how.

I wonted to see where are the rear speakers wires connected or where they are .......

Any idea and help will appreciated!

What I should do? Thanks!

Aston