What are the conditions?

[HaleyRocks]

For:

1) The new person in secret woods to appear? (the one that gives you back important items you lost)
2) The Legendary Fish Pond to change its water color? (different color fish, need either 3 population or 1st quest completed, but legendaries have no such things)

Please, spoil me!

 

[Odin]

1) The new person in secret woods to appear? (the one that gives you back important items you lost)

I am not positive, but I believe you have to actually lose one of the items listed here: https://stardewvalleywiki.com/Secret_Woods#Lost_Items_Shop