What are the best video settings when i have to mix the mavic videos with DSLR and GOPRO footage?

The same? Like I think all of them should be set similarly so that you get some consistency. Set it to the highest your lowest camera can do and set all of the other cameras to do the same.

I'd rather always shoot in 4k and have the opportunity to down sample or crop footage, very least 2.7k. the Mavic doesnt handle 1080p 60fps well so thats a non starter.

Normally i shoot in 60fps with my GoPro because of slow motion option. And a higher resolution because i have to stable some footage from it.
My 70D only can handle 1080 30fps so this will be my lowest. I think also to shoot in 4k 30fps with the Mavic will be the best solution for my setup.
But my question is more about the color grading of all 3 systems. I have always problems to fit the colors together.

You just need try it. Until Art returns - if it ever does - you are mainly looking at D-Cinelike, True colour or none probably with sharpening -1 or even -2 on all of them.
D-Log can be made to work but you need huge adjustments - I don't see any advantage unlike on the P3 Pro where it was easily best option.
Art Mode did look a lot like GoPro on native WB and Flat in Protune, I hope it re-appears soon.
The other "film-like" modes are not useless but I'd much rather record something neutral and apply any effects in moderation later thankyou.

Thank you that helps a lot. I will try that.Sharpness in GoPro Protune on or off?

The reason to have it down with mavic is it seems to oversharpen somewhat at default which can cause moiré on tile roofs and flashing along straight lines.
Sharpening is easy to add later if need be so no harm in dropping gopro to medium too, but it doesn't usually oversharpen even on high.

Thank you very much, i will try the settings. Nobody needs moire.

Trying to colour match the footage from three different capture devices on the same timeline using one filter to do all three won't work. It depends on how much of a perfectionist you are, but you will have to decide first on whether you want to use the originally shot footage from one of the devices (master) and match the other two to that footage, or whether you want to colour grade the "best" (master) footage of the three first, and then individually grade the other two to match the master. This will more than likely mean using different filters or their options to get similar looking results.

Yes thats my problem. Because of that i think its important to have mostly the same look out of the cam from all devices.
Like 4wd said i also think the best solution is to choose settings that flatten out the image, because then you got more room for your "own" colors and look.
I will try that.
The color-matching -funktion of FCPX was helping me some times, but its not enough.

Regarding 4K on the Mavic, it's not an option IMHO. 50 MBit/s is too less. Overcompresssion leads to mushy details 2.7K is the sweet spot.

Thank you i will go with this setting.

Found this:

I had a chat with DJI about this.. here's what I was able to get:

•60 mbps is a constant bit rate
•it will record at 60 mbps at 4k on either PAL or NTSC
•the bit rate will remain at 60 mbps at lower resolutions (I specifically asked about 2.7k)
•compression (rate?) is not lower at resolutions lower than 4k (i.e., 2.7k)

They couldn't give me an explanation of why for this last point, hehe ("too complicated")

Bit rate at 2.7K is about 45, I haven't tried 1080p