It’s not a joke. I had a dream last night of a song performed on the stage with 4-5 singers in backing vocals. It was not even im my genre. However I recreated the bass line and sort of rhythmic track. How can I tackle backing vocals? Should I sing 5 times for best results? Can I produce not flanging or chorusing track from one take with a plugin, Melodyne or any other one? Or duplicating tracks with detuning, delaying and filtering?

 

Maybe your looking for choir background https://hiphopmakers.com/best-free-choir-vst-plugins
or if more vocal try harmony vsts.
https://www.waves.com/plugins/waves-harmony

 

this one
https://www.jrrshop.com/eastwest-hollywood-backup-singers
or Dreamtonics Synth V

 

Sing them, you'll be happy you did for the slight imperfections in each take which enables the vocals to have soul in the context of the song. If you have other microphones and preamps than what you are using for the main vocal go ahead and use a different combination, though if not it won't really matter. Give them their own buss to glue then together. I usually compress maybe 3 to 5 dB on the way in (either a Warm Audio WA76 for up tempo stuff or an Audioscape Opto for more color and slower paced parts), use a clean compressor, after capture and in the box the Jon V firComp 2 on the individual parts, and on the buss will eq to fit the track and glue them up with something like Klanghelm MJUC or Tokyo Dawn Labs Kotelnikov GE. This works for me.