First I'm new so take anything I say wish that in mind.
From what I've been reading, no you do not need an anenome to have clowns. They are perfectly fine without but I would suggest as it was to me, to get 2.
If down the road you decide to get an anenome they might take to hosting it after time but be patient as others have reported waiting months for them to take to it.
As far as the the clown with only two strips goes, sounds like it could be a Maroon Clown (only scene it in pictures) or possible a Fiji Blue Stripe Clown. Don't let the name fool you, its still two white stripes.
Anemones and clowns don't need eachother to live and will do fine without one another, and it's not uncommon that they don't host with their anemone either, there are reports that clowns fair better (healthier) with an anemone but their is no evidence to show that the same is with anemones. Many clowns have been known to breed w/out one.
Scooby you are correct but if I may extrapolate here a little.."They are perfectly fine without but I would suggest as it was to me, to get 2." I'd only get two if they were a pair at purchase, often when you have one clown, the addition of another won't be tolerated by the first, and they will fight.