You need signatures from All four, or their legally authorized representative, whoever that may be. 

For clarity, one is an author and one is a comedian. :) 

Full disclosure I've only begun to look into the Tenants in Common rather than an LLC thing myself so I'm no authority on the subject. 

The only time you need to physically go to a registry office (at Service NB) is if you are dealing with a property that has not been migrated into the electronic land registry  {if there have been no encumbrances or changes on title since 1996, the property may not be in the registry}.When it comes to permit histories, work orders, ordinance or by-law violations, etc. these are still maintained at the municipal level (in the provinces in which we have operated) and privacy law will necessitate a letter of authorization from the property owner for you to access much of this information  ... the exception being work-order and ordinance/by-law violations which can often be accessed though a right to information request {just do not be in a hurry}.

Their authorization comes from the owner.Just as a PM will make or break a property for a remote owner, a person in this role will make or break the rehab.

I tend to prefer books that are narrated by the author — they’re more impassioned!

If not, another option is to have your parents add you as an authorized signor on one of their cards. 

The foremost authority on Lease Options of all types is @Wendy Patton.

The good thing is, you can easily brand yourself and become the authority in that area. 

You have to have expressed authorization and/or give proper notice to enter a Tenant's property.