Fairphone is a small company and has not the resources to create replacement apps with (more or less) special features for a small (maybe niche) amount of users and for all apps you could think of. There’d be not that much benefit (in particular compared to the effort needed) of that either, because there are already plenty of apps out there fulfilling most of the needs, as @Irina_Spitznagel has already mentioned. I’d see no reason in repeating this work which has already been done.
Well, whether to include Google Apps or not is a huge question and lead to equally huge discussions in the past. Please refer to the following topics for these discussions:
Why i think Fairphone OS should drop root and pre-install Google Apps
Fairphone’s approach to root on the Fairphone 2
FP2 root or not root? How?
Poll: Should the Google Apps come preinstalled with the Fairphone?
If you want to get rid of Google (or parts of it), you’ll find a lot of help here in the forum:
Living without Google 2.0 - A Google free FP2
Alternative Apps(tores): Living without Google
Living with root and Google on the FP2?
@Irina_Spitznagel already mentioned the open source version of the OS. You can wait for it to be published by the Fairphone team (only info is 1st quarter of 2016) or you can compile it yourself, if you like:
[HOWTO] Compiling Fairphone Open Source / Rooting