Interesting because I'm in the same boat. I could use a bit of help as well.
I'm redoing my 75 for my 2 yr old to introduce him to the hobby. We have been to a couple fish stores and he likes active fish. Unfortunately I know nothing about small fish like tetras.
Here is what I think I would like but do not know what quantities would work.
1 Severum
1 Electric Blue Acara
1 Rainbow Cichlid
2 Bushynose Plecos
As far as tetras I like Buenos Aries, Columbian, Rummynose, Penguin and Serpae.
I would also like something on the bottom, probably cory cats but again I don't know how many I could have.
Also this tank has driftwood, large rocks and some nice fake plants. Yes I know fake, but I am a plant murderer. I went all out and spent hundreds of dollars on plants, lights, ferts etc and I killed everything, even java fern.