Is it safe to restore the phone.apk from a stock Samsung ROM to CM9? I was using the stock Samsung ROM on my Samsung S2 i9100. Changed over to Siyah Kernel and then made the leap to CyanogenMod 9.

Although I prefer and appreciate the myriad settings and usability of CM, there are a couple of issues where I preferred the functionality of the stock ROM:


The phone.apk - not just the dialer, but the incoming call screen
and the large size buttons to answer a call or to bring up the
keypad etc. I know I can use an alternate dialer like DialerOne or dwContacts but that doesn't help me to change the incoming call screen.
Pressing the physical home button to answer a call. There are times
when it's exceedingly difficult to use the onscreen slider and a
press to answer the call is far easier.
FM Radio - although Spirit Radio works as an alternative.


For items 1&amp;2, can I overwrite the existing phone.apk and contacts.apk with the previous ones that I have backed up using Titanium Backup to return this functionality?
The answer is usually "No."  The framework changes introduced with manufacturers' UI overlays (Samsung's TouchWiz in the case of your Galaxy S II)  most likely make the stock apps like Phone, Contacts, Calendar, etc. incompatible with custom ROMs like CyanogenMod ROM that are based on AOSP (Android Open Source Project).