It depends on what you mean by mix.

In my case I am currently running main track as digital and catenary as analog with loco sliders removed for the electric locs.

In the future I am contemplating feeding the catenary through a booster and have it as digital. Not sure how feasible that is and I'm sure someone will comment as to the pitfalls of trying to do that.

Peter

Yes you can run digital on overhead....within reason.

At SUPTERTRAIN in Calgary in April we had the 3 rail layout with catenary (post 2000 catenary) and several of our overhead only loks ran fine. It was a 9 m long dog-bone layout and we used C-clips to connect the masts to the track.

I say within reason for the following reasons.

It took about 10 trips to rub away excess varnish to maintain connectivity. on a 18 m loop there were 5 spots that had issues at first but slowly disappeared.

The catenary MUST be within the stagger tolerance of the pantographs. On Marklin pantographs, there is a painted section at the outer limits and once we adjusted the masts and/or wire, connections were good. We also spiked the track to keep it from moving when we had parallel masts.
This also means that the pantographs have to be in good condition.

The mast cross arms must be parallel to the track to avoid having the pantographs hitting them. We had 5 snag areas when we first ran the loks (very slowly of course!) and eventually got them straight. This also means that the pantographs also must be parallel to the cross arms.

There must be adequate power drops for the layout. We had 4 powered masts. I would have more on a permanent layout. I would also use the Marklin all metal masts rather than the Viessmann masts that have the insulated cross arms. Yes you could get clips that will carry the current but that is more opportunity for a loose contact.

Older decoders (fx or very early mfx) may not handle the more frequent power interruptions ( you can only have one pantograph up per lok or you push the wire out of the way) compared to many more powered wheels or sliders. They get confused and have to be reset or replaced.

Marklin has been quietly reintroducing the ability to ether pull power from above or below.

As I just moved, my next layout will have catenary as I enjoy it. However I will not go crazy with it and have it over all track as a lot of catenary makes it hard to work on the layout (clean track, disconnecting and connecting trains.)

It is possible...but a little more complex and with complexity, more things to go wrong..

Another bonus with live catenary is that we can run analogue through the catenary and keep the track digital and get the best of both worlds. They share the same ground. I did that 2 years ago at GETS (Edmonton train show).

That way some AC members could run their loks on the same show layout....provided that they were electric loks.

I have not tried digital catenary with analogue track....yet

So an analog catenary system can be run together with a digital c track oval?