Stocking 75 Gallon - Suggestions?

1 male with 2-3 females is the way to go. That way the male is busy with his girls and not fighting with the other residents. I would definitely get more labs, they like to be in groups. Luckily they don't care as much about the gender ratio. No Mbuna with peacocks mbuna they(mbuna) are just too nasty.
Now to your list:
More Yellow Labs - 1 currently -Yes more Labs
Frontosa Cichlid -Fronts like to be in colonies and your tank is too small.
Fuelleborni Cichlid, Marmalade -these would be fine
Demasoni Cichlid -demasonis need to be in large groups of 12+ otherwise they kill each other.
Buffalo Head Cichlid -Not good for this set up
Buttikoferi Cichlid -won't work with mbuna
Caudopunctatus Cichlid _you can't mix malawi cichlids (mbuna) with tangs.
Compressiceps Cichlid -See above
Kenyi Cichlid -way too aggressive
Orange Leleupi Cichlid -can't mix lakes
Red Zebra Cichlid -Red zebras will cross breed with labs
Yellow Peacock Cichlid -peacocks don't mix with mbuna
Tretocephalus Cichlid - can't mix lakes
Venustus Cichlid -get too big
Red Fin Kandango -mbuna are too aggressive for this species
Red Empress-same as above

Pretty much mbuna need to stick with mbuna. Labs are a great place to start and you can keep the Labeotropheus fuelleborni. I would add another docile species like Ps. Acei. I would pick 4 species of mbuna that you really like and start from there.

Cycling with mbuna can be tough. I tried it and they all died. They don't tolerate the ammonia very well. Cycling will take about a month then you can add more fish. Wait at least a week between groups. Add your least aggressive species first(labs) then follow with the next aggressive and so on. Always rearrange the tank before adding a new group of fish.

For the most part you are right. But a lot of fish you have in the selection are from Lake Tanganyika or not from a rift lake at all. I'm not sure what your electric blue is. It may be a hap but I've seen that name applied to a lot of things. An electric blue hap can work in a mbuna tank. I would stick with mbuna and keep the hap as a center piece.

This is really too many species for a 75 gallon

• 1 trio Nimbochromis -too large for a 75 gallon
• 1 trio Placidochromis -too large for a 75 gallon
• 2 trios Psuedotropheus -These are mbuna but a very broad range
• 1 quartet (1m/3f) Labeotropheus -also mbuna and would work
• 1 trio Sciaenochromis -this is a hap and most likely what your electric blue is
• 1 trio Cynotilapia -A great group of mbuna to choose from
• 2 Julidochromis (larger species) -these are tangs
• 1 Eretmodus -also Tangs
• 1 trio Dimidiochromis -way too big for a 75 gallon and would eat your mbuna
• 1 to 3 Synodontis Catfish -great catfish for a mbuna tank. I really recommend Petricolas. Just get a group of them.
• 1 large Plecostomus _I don't think this is needed. A lot of times mbuna will eat the eyes of plecos

What i did when figuring out my mbuna stocking was to go around to local lfs and see what was available. Then I researched the species I found to see what was compatible.

From the available species groups above I suggest a Labeotropheus of some type, fuelleborni is a good way to go. A lot of fish in the Psuedotropheus catagory and psycho except for acei. They get a little bigger but are generally peaceful for mbuna. There is also Psuedotropheus saulosi. These are fun because the males are blue with black stripes and the females are a nice orange/yellow. From the Cynotilapia group I suggest, white top haras. They males are stunning and the females look nice too unlike most cynotilapias.

There are lots if mbuna to check out that are commonly available. Here are some names:

Rusty cichlid(Iodotropheus sprengerae)
Cobalt Blue Zebra(Metriaclima callainos)
Pseudotropheus saulosi
Pseudotropheus socolofi (this also comes in a pretty albino version)
Pseudotropheus flavus (these guys can be pretty aggressive but it's managable.)
Pseudotropheus demasoni (Also aggressive but mostly with each other. You can keep a single one justy avoid other fish that look like them)
Electric Blue johanni, or Maingano (Melanochromis cyaneorhabdos)

It's best to avoid Kenyis, bumblebee cichlids, auratus, and chipokae, these are super aggressive mbuna that are unfortunately commonly available.

The gender ratio of 1 male per 2-3 females,will help keep aggression under control as will some overstocking. What a lot of people do is buy a bunch of very young fish then remove extra males as the mature. This way you get to keep the best looking males and you can get a good ratio without paying a lot for adult fish.

You can get really good advice here on the forum. Not all lfs workers give great advice. Some species are more aggressive than others. Just buy more than you need and as they grow you will be able to remove extra males.

I take my extra males to the lfs.

Bill -- I think I answered this question on another fishie forum. When considering an African tank, you need to keep in mind a few things:

1. mbuna can be very aggressive, some more than others, and it's very important to always know exactly what you have. Avoid the "mixed African" tank at the LFS like the plague unless you are very knowledgeable or have someone at the LFS who really knows Africans. (I'd recommend getting rid of the kenyis as they will reduce some of your available options for stocking.)

2. You CAN mix two mbuna with peacocks successfully -- labs and pseudotropheus acei. Both are mild enough for peacocks. I wouldn't personally do any other mbuna with peacocks. (I have personally done this successfully.)

3. Peacocks and haps TEND to be less aggressive than mbuna and might be something to consider. I personally don't like too much aggression in my tanks, so I went with an all male peacock/hap tank. (I also didn't want fry.) If you don't have a good source of peacocks locally, you'll have to order them online, but that's not really a big deal. If you decide to go this route, you need to understand that you can only get one male of each species and must avoid species that look too similar. You can do a group of labs and a group of p. acei in such a set-up, with gender not important.

4. The mix of fish you posted is not workable IME; too many different species. Mbuna will interbred and then you have fry you can't distribute outside of your tank.

good luck

If it was I would rehome the Kenyis because they will grow to be quite aggressive. But if you really want to keep them then add more to hopefully spread out the aggression between them. As they grow keep an eye on the labs. Yellow labs are a little more mild mannered and may get picked on.