Well I have a 770 and love it...
I can not solve problem 3 but I know where it has already been solved check out Fanoush's web page, he made a kernel that can support SDHC cards as well as higher speeds.
Keep us up to date about this, I would be really happy to get more storage in my 770.

Edit:
Check out these pages that are along the same lines
1
2

Edit 2:
Check this out too