Another china clone of S5 GT-i9600 by ALPS

Hi all experts,
a friend of mine bought a Samsung S5 clone which resulted to be an ALPS GT-I9600.
These are the specs as reported by CPU-Z:

Display: JDQ39.I9600ZSUAMDF
hardware: mt6572;
kernel version: 3.4.5 (eng . linux . 1398851142);
Screen resolution in pixel: 480 x 854
Total RAM: 1857 MB
Internal Storage: 0.14 GB (sic!)
Available RAM: 47 MB (2%)

Now, the problems... please guide me on how to solve them thanks a lot:
1) There are some problems with the internet connection (3G) with some operators... I guess this is a common problem and I read something about IMEI overwrite, but did not understand a lot... can anyone explain me a bit the procedure? Why is it necessary?

2) The device has really few available memory, therefore it is not possible to install anything due to shortage of memory... it seems also that the "Move to SD" option for all the apps installed is disabled by default. How can we free some space?

I'd love to find an alternative ROM without bloatware and maybe root.... but any alternative is welcome anyway. Can I install any ROM intended for phones which have identical specs? Where should I search for these?

Thanks for your support guys, I'm waiting for your suggestions :cool: