Are motorhomes allowed during daytime?

Fortunately no you cannot fit a motorhome there there parking is only a dollar per vehicle which is very inexpensive however right across the street from Aliso Beach is a park and your motorhome will fit there comfortably for a dollar parking exactly across the street from Aliso Beach

It's parking on the street or in the CVS parking if you risk you vehicle being towed. No where for a camper

I didn't see any at the time so not sure.

Parking lot is small, hard enough to fit a pickup truck.

I don't think there is a place for motor homes

Didn't see any

I haven't seen any during my visits.

Unlikely, solely based on the entrance to the parking lot - I don't believe a motor home will be able to maneuver it.