ITIN renewal W-7s for purpose of filing a tax return do not need a tax return attached to them.

For an ITIN applicant using a certified passport copy issued from Passport Canada (the certifying entity) to establish identity, how long after the certifying-date on the certified passport copy does IRS accept the certified passport copy for purposes of issuing an ITIN?

Note that it is not uncommon for time to pass between receiving the certified passport copy, mailing the W-7 to IRS, receiving a rejection etc. where the turn-around time (including mail to/from USA-Canada) can result in 24-36 months passing from the original certifying date.

For ITIN purposes, certified copies of identification documentation will remain valid for as long as the original document itself is current, meaning not expired. Once the expiration date on the document has passed, a certified copy of the document obtained prior its expiration will not be valid for submission with Form W-7.