Thank you Neil. I've researched and found out that some bettas are picky and they will take awhile to adapt to the changes on food. Back in the fish farm, he was fed live tubifex worms only. Hence, I think it's quite natural to ignore the pellets. He will eat the pellets, I hope so. :)
I saw that you had a couple questions on feeding ur HM pellets. Actually bettas are carniverous by nature and feeding live/frozen (not Freeze-dried) foods should be fine. I feed my guy TetraColor tropical sinking pellets and he loves 'em! I would wait until a more experianced member replies, though. Try starting a new thread asking this, you'll get a lot more answers
Without knowing the background of the fish it's hard to tell. In general though if you want to get rid of the red wash it's best to get a female with no red who comes from a line that is not showing red. You may still get a little red but if you breed carefully in successive generations you will probably begin to see less red, although you may see throwbacks once in a while. If either of your breeders come from marble or multicolor lines there's really no way to tell what you'll get.
To get butterfly the best way is to find a female who also exhibits the butterfly pattern or to get a sibling sister to the male with a butterfly pattern. You'd be better off breeding him to a blue female than an opaque, depending on the type of opaque, however that would still be an interesting cross.