As much as I love illusions, it's questionable if you can stack so many debilitation all at once from a purely balance stand point. I can accept creating an illusion poison cloud effect that would provide heavy obscuring, since that's a basic enough illusion. Poisoning Cyanwrath with it is also possible since Phantasmal force can cause simulated damage like that. But also filling the air with a noxious scent and amplifying the sound of your viol to deafening levels is much more questionable.

At the very, very least, it could do everything except deafness. Since your Phantasmal Force can create "phantasmal object, creature, or other visible phenomenon" and "includes sound, temperature, and other stimuli,", it can be reasonable for a poisonous cloud to obscure Cyanwrath's visibility to effectively make him blind (Not not specifically blind as the condition, meaning no one gets advantage to attack him but he would have disadvantage to attack anyone he can't see) and for the cloud to cause some sort of sickening poisonous smell, but unless the cloud can also make a really loud noise on it's own it can't deafen him.

If I may make a suggestion, if you still want to inflict some combination of blindness/deafness, try emulating a [url=https://www.dnd-spells.com/spell/hunger-of-hadar]Hunger of Hadar[/url] spell instead. It'll still do the same thing such as block his sight, and then you could say that all of those noises are just amped up to 11.