I need help with linked apps

Apologies if this is in the wrong forum, I’ve posted it here because it’s fitness related.

Over the past few months I have looked at various apps for exercise on my Android phone – mapmywalk, Runtastic, etc, and I have linked them all (where possible) to mfp, just so I can see how well the integration works for me, etc.

I am mostly happy with mapmywalk as an app as far as functionality goes, but I don’t use it as much now I’ve got my Fitbit (which is also linked) in case I duplicate my calories gained by walking. I now find that Runtastic looks pretty good aswell, now that I’ve installed the 6 pack app, which shouldn’t won’t mess with my Fitbit stats.

My issue now is that I’ve got so much linked up and I don’t even know anymore what to use when I go for a walk, etc – should it just be my Fitbit (which means I’d have to unlink everything else), or can I use mapmywalk aswell? I don’t want to double up on exercise calories, I only want them credited once.

To confuse myself yet further, I am also thinking of buying a HRM at some point, but I haven’t even considered how this will affect my figures yet!

Can anybody clarify this minefield that I have created for myself?