mobile

Hello guys..

I am an ATnT Samsung galaxy S2 i777 user. Some may be aware that the logcat files generated by Samsung at times causes issues by exhausting the memory reserved for the apps. My phone was plagued by the issue and i wasnt aware of the exact problem.
As a result, i kept moving apps/data to the external mem card as much as possible to keep the phone cured of the 'device memory low' warning sign. I was away from the scene due to hectic schedule and as there wasnt any big need to install new apps/features either, i wasnt bothered too much.

Finally one day the phone rebooted while i was asleep, and i woke up to find that much of the customization was gone. No Gapps, No Apex launcher, No Amazon app store, many apps (incl Titanium backup) missing.
Forced to google, found out the *#9900# trick and wiped off the excess logcat files. The memory status got straightened out, but the phone wont restore to the earlier state even after reboots.

I was running Shostock ROM, and it was about time i moved to either Kitkat or even Lollipop based ROMS. And this is what i plan to do now that i have the perfect excuse. Before i pulled the trigger, i wanted to clarify some points out so pls do lend me a helping hand here.
Have chosen Carbon ROM as my next. (Geekynimrod and rogsersb11 been superb with the work)

1) I have moved a lot of apps/data to the mem card. Once i have flashed the new ROM, will this data interfere with the new setup?
2) I would ofc need to empty the mem card of the data which i dont require. How to clean up the moved app/data if they are of no use?