Everything you mention possible in theory but unsupported.
Tails + Whonix: Perhaps Whonix Live or Disposable VMs are an alternative?
Tails through Whonix-Gateway would lead to Tor over Tor. Discouraged.
Tips on Remaining Anonymous
Tails using Whonix-Gateway is possible in theory but unsupported.
Kali: Allow discussion anonymous pentesting in Whonix forums?