I am wondering, is it possible to change the modding option in the menu to actually make real mods.

So for instance there are things like unit and dropship options in which you can customize the characteristics of the units. There could also be an option to import sprites. (Or even create them in game if it's possibe.)

This could really help newbies like me.

I suggest that you investigate modding via the traditional means. It's very simple to change the things you describe.
The easiest way to learn is by looking at the Vanilla stuff or mods, and changing things and seeing what happens. It's pretty logical, and if you have any problems, we'll be happy to help.

Here are some additional resources:
Everything you need to know about modding in CC
Your first gun
Your first actor
How to put CC sprites into the palette.

Thank You!

Modding seemed quite complicated but these links help a lot!

i started modding by making a BADASS laser rifle with 2 of spread and 3000 rounds.i made it worth 10000oz.works well.