Daisy chaining multiple sdr's

Can this be done by daisy chaining them?

Yes*

I (…) want the “clock out” (…) to reference (…) the external reference.

The frequency will be exactly the same and the phase will have a slight constant offset. And that would be the same for all SDR’s that I know in that particular configuration (1).

ref: Page 3 of the schematic gives the block diagram for the clocks.

If I’m totally honest I can’t see any way of getting 1 and 2 in your diagrams to be equivalent with any SDR using a clock in+out that I know. All of them have some form of clock buffer and that will change the phase slightly from device to device but by a constant amount. Even the cable will adjust the phase by a small amount.