Assuming just from TTC - From memory Ferry is 600 people per boat, assume 3 (I don't think they often run all 4), 10 min each way, 5 min load/unload time. So each boat can do 2.4 round trips per hour, ~1440 per boat, 4320/hr.
Monorail has capacity of 360, 3 trains. 5 min to park, 10 min from park back to TTC, 5 min load/unload. So each train 3 trips/hour, 3249/hour total.
This is all back of the envelope and I welcome someone more knowledgeable providing more accurate daya.
The big thing though, is if they charge for the monorail, many people won't ride and likely monorail doesn't run at capacity. The boats will have to absorb the extra traffic, and likely will back up.