Beautiful tank.
I was going to post that spray paint will melt the foam, but it seems like I clicked in to late hahahah.
I loooove FW tanks sooo much, but more so planted ones right now.
Cichlid tanks are cool but if I may just suggest something.
The choice of Cichlid you picked so far is kinda plain colors. Why not spend a bit more money and pick up some more exotic kinds.
An example of my all time favorite is:
Electric Blue Jack Dampsey
There kinda pricey but the colorful Cichlids will really attract the eye more then the plain earth toned ones.
...Or what about Discus Cichlids?
Also if your going to put plants in that tank there all going to be lacking in growth because of the lack of CO2.
If you stock to much as they get bigger they will starve for CO2 during the day.
Just a heads up.
Oh ya. On a side note. Thats really nice substrate you mixed up, its exactly the color I want mine to be when I redo my FW tank.