[Q] A few questions regarding Android

I have a phone Galaxy Ace plus. I rooted it and recently installed SSHDroid to it. I have little knowledge of Linux so after I ssh in, I did wander little bit and found this,

1)

- All personalized settings of user are kept in /data/data
- Each app is assigned a special userid/groupid and has rights on its particular directory only.

So,

If I purchase a new phone and lets say I install temple run in it, so I copy the com.imangi.templerun/* from the old phone to the new phone and copy the permissions from the parent folder (com.imangi.templerun) of the new phone so will I get my high score, achievements etc in the new phone ?

2)

At the root there is a soft link /sdcard which points to /mnt/sdcard. Is it possible I change this link to /mnt/sdcard/external_sd so when I move any application to 'sdcard' it goes to the external_sd and not in the USB storage ?

3)

There are apk's in the /data/app ? These I suppose are installers so what is their function in the phone ? Can I safely delete them to free some space ?


Apologies for being a noob, but I am new in Android.

Thanks.