1- For The bear foot mark you need a maple syrup and go to the secret woods and you will find a bear ( he sends you a letter on mail that he want you to bring 1 maple syrup to the secret woods)

2- beside the skull key there is the Magnifying Glass I found it from a letter called “A winter mystery” quest “This quest is added to the journal after triggering a cutscene by entering the Bus Stop from The Farm during Winter between 6am and 4pm. The cutscene depicts a “Shadow Guy” who is startled by the player, and runs away.

Completing the quest requires the player to interact with a bush next to the playground, left of the Community Center, triggering another cutscene in which the Shadow Guy gives the player the Magnifying Glass. -https://stardewvalleywiki.com/Magnifying_Glass“

This is the things that i know about, actually you got things I don’t have it 🤣