Soilless, Rooting cubes & Coco coir/Vermiculite?

Is it necessary to root the seedling first in the cube, and then transplant it into the Coco/Vermiculite mix?

Or, can I just stick the cube in the coco/vermiculite mix and call it a day?

Thanks for your experience!

You can go straight into the coco and vermiculite but if it was me I would be using perlite instead of vermiculite as it aerates a lot better producing much more oxygen for the roots

Vermiculite is a bad idea........perlite is what you need......vermiculite retains water and perlite increases aeration.
I start in rapid rooters and place them direct into my coco.......it helps in keeping the rooter from drying out.

Rooting plugs absolutely are not necessary, but I use them, because I have personally had better results when I use them.