Holy conflicting information, Batman!
There is no evidence that I have seen, in 17 years in the hobby, and 3 years in the business, that farm raised clowns behave any differently than wild clowns. Instinct and Mother Nature are far more powerful than any human arrogance.
There will always be exceptions to rules when individual animals are concerned.
I generally do not recommend mixing species of clown in the same tank, but people do it because they want to (and who am I anyway, to tell them what they should or shouldn't do?!), sometimes it works, sometimes it does not.
Anemones have little or nothing to do with it. I've seen a tank-raised tomato clown, who never had an amenone, turn ugly once brought "home" and kill the partner she had been living with in my store for 4 months, then she killed a cardinalfish. The clown was returned and she has been a model citizen since. Recently she took up residence in a Heliofungia she is housed with.
On the other hand, I've seen people keep Maroon, Tomato and Perc all in the same 30-gallon tank. IMO that's begging for trouble, but they got away with it. You just never know until you try.
One thing that nobody is advising you about here, is that the natural host anemones for A. percula and A. ocellaris (your "nemo-clown" :roll: ) are carpet anemones. Hard to ship, hard to keep, they get absolutely massive (even for a larger tank) and they will indiscriminately eat other fish. Still think that is a good idea? I don't. Sometimes A. percula and A. ocellaris will take to a Bubble Tip Anemone, but it's hit-and-miss. Sometimes they will choose a coral host, after nearly 2 years my A. ocellaris have adopted some zoanthids to live in. There is no guarantee that the host you provide will be accepted by the clowns, and IMO it's not a good idea to add any anemone to a new tank. Give the system time to mature, and *maybe* it might be a good idea down the road. Then again maybe not.
Chances are that all the "percs" will get along, as they are similar. Eventually you will end up with either a "family group" (sexually mature female & male and 2 subordinate males), or 2 pairs, in the latter case, they will probably keep to opposite ends of the tank.
Is it a good idea? Up to you -- none of us here can predict what will happen either way. I just hope that I've cleared up a few myths/misnomers.
HTH
Jenn