There is a ported S7 edge for the S5 G900F. There's also a 5.1.1 S6 port for the S5. You guys might wanna try it. I am currently using sixperience S6 edge TW Rom 7.2 on Globe locked S5. Good battery life. S6 features working. S6 camera is not fully working but it usable if you don't use much of the features like dual cam, etc. It has an option to install the default s5 camera which works ok.
Note: use a custom recovery that works on an aroma installer. I use TWRP v2.8.5, twrp 3.0 doesn't work for me.