It's too bad that lost items don't come with instructions for how to reunite them with their owners. I can't imagine your coming up with more reasonable solutions to these dilemmas. There is never an obviously right answer in these cases, only a best guess.

Of the items you mentioned, the expensive tent beside the trail is the prickliest. It is because I have been in your position as the 'finder' of such stuff that, if I ever leave something by the trail that I want to retrieve later, I find a place that is easy to memorize and return to, where I hide the item from view.

But 99.9% of the time I do not leave anything behind deliberately! I take it all with me, as the safest, best, most foolproof way to deal with not losing things. I recommend that approach to others, too.