I know some types of fish need to be kept in groups, my question is, lets say zebra danios, is it acceptable to have 2 zebras, along with 2-3 glowlight danios, and 2 lepard danios as a group? same with tetras... 2-3 neon,2 cardinal,2 rummynose, or does each specific type of danio, or tetra need to be kept with its own kind as a group, thanks in advance for replies

Each species should have enough other members of it's own species. You'd be surprised how nice a large school of the same species of fish can look when moving together. IMO it is much more impressive than a jumble of different species mixed. Either way, fish need others of their own kind for the proper schooling behavior.

Most shoaling fish have hierarchies/pecking orders, especially in a body of water as small as a fishtank. If they don't have someone to peck and get an appropriate response from, they start pecking at random. Fish from outside their Genus may have different communication systems, and communication and rank quickly break down. We then decide we have a 'mean danio' or mean something else, and try to figure out why everything is acting so strangely.
A key reason to keep little gaggles of fish of one species is to let them find a comfort zone in sorting out the king of the hill.

You may do better mixing South American (SA) tetras with SA tetras, Asian danios with danios and barbs etc, on the principle that this behavior is genetically determined, and fish from the same region are less likely to have developed different 'languages'. I have a mixed African tetra tank in which the fish communicate smoothly, but they are all from the same river, so it makes sense they'd respond to new situations in similar ways.

All of the danio types you've listed are actually the same species, just different color morphs. I asked the very same question not too long ago and the general consensus is that they will all shoal together with no issues.

As for the tetras, I've heard accounts of people having their cardinals and neons shoaling together, but rummynose are a much different type entirely. They really need lots of members of their own kind as they tend to school much more tightly than most other tetra species.

Colour speaks loudly. A silvery reflective fish like a rummy nose reflects sunlight as a camouflage, and can be expected to live in large groups often up around the surface or where the light comes into play. As silver creatures, they are sunlight creatures, and use the light to confuse predators. To do this, they have to be in groups, and are more confident in shoals.
Darker fish are often from darker waters, or plants and shade, and if small, also tend to feed in groups. They are often less dependent on big mass shoals for defence against predators. They sometimes handle smaller groups better without getting nervous or disoriented.
Either way though, given our small numbers of fish in a tank, you have to respect their social/behavioral needs to a certain degree, or you get weird behavior. For example, zebras love to race. That's hard to get into if you always race the same guy.
Luananeko's right - zebras are a natural species, glowlight danios are genetically modified organisms based on zebras and leopards are closely related and debated zebra versions. They'll run together fine. That's a different kettle of fish from the biological species we find with tetras.

i have 3 zebra danios and one yellow one, and the yellow one is always with the zebras darting around the tank. on the other hand, i have cherry barbs and gold barbs and they school seperatly.

With the barbs, it's body shape. They don't care what we name them - they occupy different ecological niches so they behave differently. The zebras and the gold are the same fish - the gold modified by fishkeepers, not nature.

the gold barbs for some reason have really grown on me! im not a lover of gold coloured fish as they remind me of goldfish but i think im guna keep them if they get on with my eventual guppy clan!! i think it might be becasue they play with the oscar, they'll swim into his side, go up to him so he sees them swim back into there side where he cant fit, he sits and wait till they come back!!

mustardlips, id get some barbs too!! really entertaining.

I'd be careful about putting barbs with guppies... Barbs have a tendencies to love to eat fancy guppy tails.