Ok, I've been thinking and reading about each clue, and at first sight each one seems very easy to answer, but I don't think so, for example most of the answers about what is gathered at the club silencio tells that is the blue box and the blue key... STOP! at that time there's no key at Club Silencio. So, what is gathered? this is my interpretation:

1.- 3 Languages: French, Spanish and English- As far as I know, all the characters speak in english, but only a few speak in spanish (Cookie, Rita, Adam at the dinner) but who speak in french? There are many theories that says that Aunt Ruth Does because of the book "A tout paris" but also we can think that Betty does because she also came from Canada where many people speak in French.

My point is that unless I'm totally wrong, no one is able to dream in a language that doesn't know, so if it's a dream , who does it belongs?

2.- Other thing gathered at this point are the stories of Rita, Betty and Adam, up to that point only Betty have crossed with Rita and Adam in different moments, but at Club Silencio there's Cookie a character from Adam's story so this way the 3 stories are somehow gathered.

Please Comment

I like both of your observations. Things to think about. Keep the ideas flowing.

Well, Betty gathers herself after shaking uncontrollably.

But seriously, gather can refer to the people 'gathered' there. Ever notice that everyone there is a couple (all sets of 2)? So, couples are gathered there? And (just an observation), the two we see at the top row on the right appear to me as mannequins...

Knowing how Lynch likes to play with words, I looked up the definitions for 'felt', 'realised' and 'gathered'. Notice that 'realised' is not spelled with a z.

Here's what I found for 'realised':
Adj. 1. realised - successfully completed or brought to an end; "his mission accomplished he took a vacation"; "the completed project"; "the joy of a realized ambition overcame him"

There were many for gathered, and there are a few that I find interesting (mostly 2, 5, 10, 11 & 12):
Vb. gather
1. to assemble or cause to assemble
2. to collect or be collected gradually; muster
3. (tr) to learn from information given; conclude or assume
4. (tr) to pick or harvest (flowers, fruit, etc.)
5. (tr; foll by to or into) to clasp or embrace "the mother gathered the child into her arms"
6. (tr) to bring close (to) or wrap (around) "she gathered her shawl about her shoulders"
7. to increase or cause to increase gradually, as in force, speed, intensity, etc.
8. to contract (the brow) or (of the brow) to become contracted into wrinkles; knit
9. (Communication Arts / Printing, Lithography & Bookbinding) (tr) to assemble (sections of a book) in the correct sequence for binding
10. (tr) to collect by making a selection
11. (tr) to prepare or make ready "to gather one's wits"
12. (Clothing, Personal Arts & Crafts / Knitting & Sewing) to draw (material) into a series of small tucks or folds by passing a thread through it and then pulling it tight
13. (Medicine / Pathology) (intr) (of a boil or other sore) to come to a head; form pus

And lastly, 'felt':
n.
1. a. A fabric of matted, compressed animal fibers, such as wool or fur, sometimes mixed with vegetable or synthetic fibers.
b. A material resembling this fabric.
2. Something made of this fabric.
adj.
Made of, relating to, or resembling felt.
v.tr.
1. To make into felt.
2. To cover with felt.
3. To press or mat (something) together.
v.intr.
To become like felt; mat together.

And, of course, it's the past tense of 'feel'.

Are curtains ever made of felt? Lol! I know they can be gathered...