Coloration is not an accurate way to identify Ocillaris and Percula, espcially in small ones. True Percula do not always develop the dark black coloration around the white bars and I have seen plenty of Ocillaris with a decent amount of black outlining the white bars.
True percula have 11 dorsil fin rays and typically the eye coloration around the pupil is the same orange body color. Ocillaris Clowns have 10 dorsil fin rays and the eye coloration around the pupil is black / grey.
These appear to be Ocillaris. I can't count the dorsil fin rays but I can see the eye coloration as dark around the pupil. Additionally, Percula and ocillaris do not mix well together, Percula regularly will beat up Ocillaris.
The differance in coloration can be caused by numerous factors. I have imported ocillaris from Bali & philipines and there is a signigant differance in coloration. The ocillaris from Bali are much better colored, richer orange and often more black where the ocillaris from the Philipines are often pale, lacking much black coloration. Another factor is captive bred clowns. Much like the problem with most freshwater fish, the quality of mass produced salt water fish is rapidly on the decline. Paler colors, bent mouths / faces / gill covers & "mis Bars" are deformitys from non selective breeders. The paler / lighter colored clown may also be a result of environmental factors. If it was maintained in a poor environment and not fed a quality diet, that could also influence the lighter coloration. Not all that uncommon in commercial holding systems. it may or may not develop a more rich color in time.
As per anemone, Ocillaris are picky, Carpets & saddles (gigantean & haddoni) and Ritteri anemone seem to be their favorites. It's hit or miss with other anemone (more miss than hit). They don't need anemone at all but it is cool to pair them up. Pairing up with corals is not uncommon but not necessarily desirable. Clowns do it for lack of better option and most corals are not fond of it although some may tolerate it.
The clowns in this picture appear to be too small to have their sex determined yet. Most likely what's going to happen is the One with the stronger coloration will develop into a female (bigger / more dominate) and the smaller will turn into a male. I am betting they are non sex right now due to size.
Good looking fish, clowns are fun.....Joel