Nice image. I like your approach of putting the horizon through the center of the fisheye to keep it straight.

1) Tough call. I find photomatix exaggerates things like noise & CA and on some images I just give up. I guess I approach CA removal like you did, but in my case it's because I first convert NEF to TIFF using NX which does auto CA removal. It would be an interesting experiment to try to remove CA after tone mapping.

2) Ghosting can be a problem with moving foliage. I've done all kinds of creative things to try to eliminate this before or after tonemapping.

In this shot the foreground flowers had moved quite a bit between bracketed exposures (3-shot, 2-stop bracket), but because they were mid-tone they were pretty well exposed in the middle image, and the real HDR problem was in the sky. I took the middle image in the bracket and processed it -2 & +2 stops, blended the flower area from the processed shots with the other 2 shots in the bracket, and from that went to photomatix. The exposure blending was right on, and of course this eliminated any possibility of ghosting in the flowers
http://www.tempered-light.com/image.php?id=1&parent=22&page=0

In this shot the vines on the left were ghosting, but the area that needed HDR was the sky and a barn so when I noticed the ghosting in the tonemapped image I blended back in the vineyard area from a single well exposed shot in the bracket.
http://www.tempered-light.com/image.php?id=300&parent=13&page=0

Larry - a Bay Area Nikonian
My Nikonians gallery

www.tempered-light.com