I'd make sure everyone involved with the project has read all seven books first before they even start to write a single script or screenplay!  

The next poster has been given the opportunity to BE in an episode of Netflix's Narnia as a minor character (one or two spoken lines) of your own choice...

Hmm. I would probably pass and let someone else have the opportunity?

The next poster receives a mysterious package in the post.

I'd inspect it from every angle, contemplate the postmark, think about it for a bit, and then open it (carefully). It would probably be a mislabeled delivery from Amazon, meant for the neighbor, but... it might be more.

The next poster finds themself alone in Denver, CO, for a day.

I enjoy visiting some museums and bookstores.

The next poster gets a chance to go to the Moon.

I would be terrified , but would marvel at the sheer vastness around me. 

The next poster is handed a plane ticket to anywhere they choose. 

I would make sure it didn't expire anytime soon and start detailed planning for a long-delayed trip.

The next poster receives a huge gift basket on their doorstep.

I'd open it and share out the contents with friends and family. (Except for the chocolates, of course, which are all mine by default. ) And send a thank you card to the giver, of course, unless it was someone anonymous...

The next poster finds him/herself in Narnia, during the Golden Age of the Pevensies!

I'd visit during the coronation of the Pevensies, give my congratulations, and enjoy the party! 

The next poster is given a jet pack.

I would very carefully try it out.

The next poster receives a mysterious note in the mail.

I would eagerly open it, hoping it was either an offer of money or the prospect of a spectacular adventure.

The next poster finds an injured fox lying on their doorstep, pleading silently for help with its big golden eyes.

I would wrap him gently in an old blanket or towel, put him safely in a box or crate, and call an animal rescue charity. (I have actually done this several times before, back in Australia, with injured birds and abandoned baby possums, and once with a severely injured little cat who sadly couldn't be saved.)

The next poster is given a free ticket to the holiday destination of their choice, anywhere in the world, guaranteed COVID free.  

I'd check for the fine print.

The next poster finds an old letter in an used book they purchased.

I would see what the letter says and try to find whose letter it was and what they wanted or asked in the letter. If it was anonymous, I would keep it.  If it had a directly stated name, I would return it to the shop manager and try to find whose it was. 

The next poster finds a treasure map on the wall of the bathroom they are renovating.  

I'd hire a ship and a crew and set sail to find the treasure! (And hope that Long John Silver wasn't among our shipmates... arrrrrrr! )

The next person has the opportunity of spending one day in the company of any famous person (real or fictional!) of their choice.

I would spend it with King Edmund the Just!  

(okay obviously) 

He is one of my favorite all time character. I would ask him questions all day about Narnia and wish to get to know him as much as possible. It would be a big honor to spend the day with a king! (we would also check the wardrobe ) 

The next poster would be able to master one talent (one talent only) with no beforehand practice whatsoever.