I've heard of people tripping on shrooms on antidepressants, but I imagine the trip is also probably blunted like it would be on LSD.
Serotonin syndrome is usually kind of rare but not impossible. Hell, I've given myself mild to moderate serotonin syndrome before by mixing stuff like venlafaxine & DXM.
I think if you want the best trip & no worries of serotonin syndrome side effects, I'd skip your antidepressants for at least 24hrs.
Also the seroquel will probably take all the fun out of it since it's going to block dopamine & rewarding effects, so I'd skip that as well.
Although I don't really recommend anyone stop their meds, since I'm not a doctor. But if you're going to trip, it's best to do it safely. And skipping those meds would be your best bet, so that there's no interactions.
It's also good to have a benzo on hand, just in case you were to get nasty side effects or serotonin syndrome. Popping a benzo right away at the first signs of serotonin syundrome, especially one with strong anticonvulsant effects could save your life in that sort of situation.
Some serotonin syndrome symptoms to watch out for -
Nausea / Projectile Vomiting
Shaking
Feeling like your insides are burning up
Sweating profusely
Confusion
Agitation
Seizures / Convulsions
Hand tremors
Myoclonus
etc..