Keep in mind that lions are Non-Aggressive predators, most eels (snowflake is usually OK), Large Angels, Puffers should be watched, many Triggers, these all are known to prey on lions.
Avoid adding any Frogfish, Scorpion fish or Anglers, they will prey upon each other. Which ever fish grows the fastest eats the most........
Look at it this way, Volitans grow fast, much faster than dwarfs, they can eat around 1/2 their size, if you plan on keeping your lion well fed so it will not eat the smaller fish than over feeding will eventually kill your lion.
TexasMetal said it right here "Individuals always have exceptions among them."
I do have two smaller blue throats 3-4 inches with my large volitans 12-15 inches, but they are fast, could my volitans eat them "Yes" .... lol However I would not put my little clowns in that tank, they would be food. It will also depend on what species of clown fish you are thinking of adding.
Kaye