Sync devices from Nokia / HealthMate to fitbit app simultaneously

[runnerunner]

Hi,

I would like to use the fitbit charge 2 HR (normal workouts) and the withings/nokia go for swimming.

a) can I sync the withings/nokia go to the fitbit app, and is there any data loss?

b) can i sync both devices into the fitbit app so the dashboard shows me the sum of all my activitiy and I have the overview in one place?

c) can i then also sync the withings smart scales?

d) can I then also sync the withings aura sleep system into the fitbit app?

reason i am asking is that i prefer the fitbit fitness tracker with the heart rate monitor and its activity recognition.but i like the above withings products (which also have their own app HealthMate). I would like to have it all in one synced ecosystem though.

Thanks in advance for your advice

Moderator Edit: Updated Subject For Clarity

[SunsetRunner]

All I get it this now. So it appears this integration no longer works.

{"errors":[{"message":"redirect_uri_mismatch: The redirect URI provided is missing or does not match partner callback url"}]}