Will the LA1 do a data wipe if flashed with mobile odin pro ?
Yes. A wipe ROM will always wipe, no matter how you flash it.
(...)nandroid backup... I did not find this pgm.
When creating a backup using Clockworkmod Recovery, either manually in Clockworkmod Recovery itself or by starting it "remotely" using the CWM app, this will create a "nandroid" backup. Earlier, in the "olden" days, it wasn't just called "Backup" in the recovery but really "nandroid". Nowadays the option which does a nandroid backup is just dubbed "Backup".
As opposed to Titanium Backup, a nandroid backup is a one-to-one exact image of your device the moment you pull the backup. Titanium Backup does not image the whole device but APK and custom data belonging to APK only.
But i received a msg saying "MD5 Mismatch"...
I had the exact same problem, tried to restore Data and got MD5 mismatch...
Same answer for you both: it's a bug in nandroid/Clockworkmod recovery. Can be circumvented very very easy though. After flashing, boot the device, skip all initial setup steps, launch CWM app, select restore, select the backup done before the flash, untick all options except "data" and proceed. Interestingly, when launched through the CWM app, the restore will complete. When launched inside the recovery itself, it fails with the stupid MD5 has bug. It might be possible, that the first time you try to restore, it just boots into the recovery, does nothing and just sits there. If that happens, just reboot, launch CWM, select restore, untick all except "data" and the second time round it usually works. At least on my and my friends device.
Which CF Root Kernel will work with LA1 ?
All, differences in Kernels are minimal. If you take a more recent kernel (KL7/8) you'll be able to use the flashlight widget with 3 levels, earlier kernels only know about 1 level.
If I use ROM Manager to backup, I need to install ClockworkMode. Will it cause trouble for me to use mobile odin later? Will I retain my CF-Root?
Yes. No. Yes. If done correctly.
Oh, so let me get this straight, if there were a LA1 CF root kernel then you could just update then root it with the new kernel. Instead without it you have to root your current rom first, then upgrade via mobile odin pro?
No. Availability of a cf-root kernel has no influence of direct-root-ability of a ROM. A cf-root kernel only means the kernel which was in that ROM slightly edited and equipped with the custom Clockworkmod recovery. That's all. Any recent kernel - read above - will do though.
I believe someone was asking about FM, right? FM is the "FM Kernel" by riversource. It's a custom kernel, obviously quite close to the cf-root kernels but with some added goodies like additional governors which can make the device react more snappy, for example. Or save battery, or whatever cpu governors can all do.