Yes, bypass the bottle if you can! The bottle is very hard to wean from, so if he's interested in sippies or regular cups, I say go for it! I had one child (my daughter) who used a bottle and one (my son) who went straight from the breast to a cup. Okay, actually, he did both breast and cup - he finally left the breast behind the week he turned four. He used cups at the table and out in public, and nursed during "quiet time" at home.
My daughter, on the other hand, had to be pushed pretty hard to give up the bottle (which she had used part time since infancy - she also breastfed until she was 2 years 10 months) because it was very easy to drink from, while cups made her work harder, and she didn't want to do that.
Neither of my kids had diminished interest in the breast because of either the cup or the bottle. But, as you can tell from how long they nursed, they were both serious milk-munchers and I never had any issues with milk flow or supply, even when I pumped.
If you can avoid bottle use, I think you may make life easier for both you and your son.