The Meowlody Trophy can be unlocked by collecting every Music Sheet in Stray.
Fixing the Tracker from Seamus requires you to get the Super Spirit Detergent, Electric Cable, and Poncho in Stray.
Focus on the four enormous clocks on the wall to find the code to the Secret Room in Seamus’ Place.
You need to have the Super Spirit Detergent and Electric Cable first to get the Poncho from Grandma in Stray.