Export stock samsung keyboard+gallery from my S4 to my LG G Pad?

Hey guys!

So I am using a stock samsung 4.4.2 firmware on my 9505, and I have gotten very used to the keyboard and I really like it.
I also love the stock samsung gallery app.

I just bought a LG G Pad 8.3 tablet (also running 4.4.2), and I would really like to use the gallery and keyboard from my S4.

My S4 is rooted so I just took the .apks from the system/app folder, transfered them to my rooted G Pad, put them in the system/app and fixed the permissions.

It did NOT work.
So I tried installing them as normal apps, it did NOT work.

Is there anything I'm missing? Maybe some lib files or something?

If anyone could tell me what files I need from my 9505 in order to get the stock samsung 4.4.2 gallery+keyboard to work, I'd be really happy!

No one?
How hard can it really be to 'port' two apps from one device to another when they're both running the same version of Android?