Here are my questions:

1. Can someone explain the fall Festival and how it works??
2. How do a add a third party member?
3. Is there some sorta item/pet whislist so when your trading you know what the other person wants?
4. Is there a way to bookmark topics so we could easily get back to them?


That's all the questions I have_{(for now)}

2. How do a add a third party member?

Unlock Umbra Forest (by finishing all the areas in Viridian Meadows), then go into Sanctuary of Saerielle's Plaza. You have to pay to unlock it.

3. Is there some sorta item/pet whislist so when your trading you know what the other person wants?

Nope. At best, the other user manually makes a list they want, and posts it somewhere, whether it's on forums or in their profile.
Systematically, nope.

4. Is there a way to bookmark topics so we could easily get back to them?

Besides bookmarking it in your browser? Nope.

1. Can someone explain the fall Festival and how it works??

Every season, there's a 2 week (or so) festival. There are a few constant aspects to each festival:

-a special festival-unique zone, which is just a map you can navigate. (It's a new interface of exploration that you haven't seen yet)
Within that zone, you can find:

-unique bosses that drop limited time festival-themed items
-limited time themed wild pets that appear only during that specific festival

There are also:

-wheel of dreams, which is basically a wheel that you can "spin" for prizes, which include very special limited time pets, a jackpot of gold, philters and traps, and holiday currency to get stuff from the holiday store

-a holiday store to buy festival-themed stuff with currency, which you can find from nurturing pets during the festival, defeating bosses in the festival zone, or the wheel

-forum games that you can participate in, you can find them in the Official Games forum

To each festival, there are unique aspects as well. The Fall Festival had:

-Trick or Treat, which is an interface where you can go to each user and "trick or treat" them, and they can give you candy, which you collected to trade in for a Handful of Candy, which gave you prizes

-Mojos for Hexamora, a contest where you catch a certain species of pet with a special festival trap, and the top 20 people on the site who catch the most species of that pet get a special pet prize, and you can randomly get the special pet prize from catching the species with the special trap as well

There's different festivals that have different things, but also similar characteristics.
The 4 seasonal festivals (fall/spring/winter/summer) are usually 2 weeks and are very big with content.
There are smaller festivals (week of love, week of fortune) that are 1 week or even just 3 days.

How exactly do you get a Sylesti essence? I'm slightly confused about it.