Kao, welcome to TBN. Also, great description of your intended uses. This is an outstanding example of when the appropriate tractor size doesn't correlate with acreage. I think you are looking at the right size, and I would second the suggestion to consider a B3030 cab - slightly small, but the cab would be soooooooo nice to have that you probably wouldn't mind a couple extra hours in the seat. I think a B3030 would be perfectly adequate if you're willing to use a 4' wide brush mower. If you want 5' or 6', it will be too small.
I would strongly, strongly recommend HST for your planned uses. FEL work is much easier and somewhat faster with HST, and mowing can be too if you have obstacles to mow around.
Too bad that the JD dealer isn't good, because they make really nice tractors. Fortunately Kubota and NH do also. I think dealer quality is roughly equal in importance to quality of the tractor itself. In your situation, I would likely choose Kubota. Only caveat is that I wouldn't expect the local dealer to give you much service if you buy from far away to save a few bucks. However, the farther dealer may be willing to give you free transport for service, which would cancel that out. I would discuss service as well as price with both dealers. I disagree with IslandTractor on your likelihood of needing Kubota service, based on my own shopping and reading the Kubota forums here. It's not a knock on them, just a statement that all brands can have issues and I wouldn't buy something planning to have no issues.