No. A joint owner has every right to the vehicle, just as much as you do. That includes knowing where it is, and having access to and usage of it.
No you can not "legally" hide a vehcile being sought for repossession. In most states you can be charged with a felony for hiding one.
No.
legally registered vehicles are required in most states to have insurance. go through your state motor vehicle agency. and put aside time.
yes
hold it over steam from a kettle. hide glue softens with moisture.
No.
I would wear loose fitting clothing to hide joint pain. Less constricting clothing will help with your ease of movement and also make it easier to ge the clothing on and off.
Park the vehicle in the shadow of a larger object
Yes. If the person who is on the lease actively attempts to leave the state or region of the country AND it is proven they attempted to HIDE the vehicle, then some states allow the owner of the asset to declare it as stolen and it may be on the BOLO list for police in your new local area.
repesession
He will report it as a stolen vehicle.
Not recommended. The vehicle must be titled into the name of the legal owner. If the intent is to hide the driver from the insurer in order to get a cheaper rate, then it would be a form of insurance fraud.