Le Muffin Plus

No as per yellow pages website they are only open mon-fri 8am-6pm

Yes

Midnight https://www.impark.com/ottawa/world-exchange-plaza-parking-garage/#Rates

Parking is open 24 hours but you cannot park overnight unless you have a parking slip from the Capital Hill Hotel or the Sheraton on your dashboard saying you are a guest at their hotel. The building itself closes at 9PM every night so you will need to walk down the parking ramps you used to bring your car down or use the 24 Hour Access Door on O'Connor Street between Shoppers Drug Mart and the O'Connor Street lobby. You will need to look at a 90 degree angle when walking around there as it is hidden behind a corner in the wall. I'm a former employee there.

6'4" at both the Queen and Metcalf parking entrances.

No... City hall parking is free after 6...u can park there

There is on P2 by the O'Connor elevator lobby on the pillar on the left as soon as you exit the elevator lobby but you cannot park overnight unless you have a parking slip from the Capital Hill Hotel or the Sheraton on your dashboard saying you are a guest at their hotel.