Learn English – What are these containers called

The German Wikipedia page for Inflektiv also provides a synonym—Erikativ—which is "named for Erika Fuchs, who translated Mickey Mouse comics into German and used the form frequently". Going by Google's results, Erikativ (or Ericativ, sometimes with an 'e' at the end) appears to be just as popular as Inflektiv.

There is an interesting (and exhaustive) paper by a Mark Lindsay [PDF] on the subject of the Erikativ from a linguistic point of view. He states:

The German Erikativ construction (also known as the Inflektiv (Teuber 1998)) is a phenomenon that existed prior to the mid-twentieth century, but first developed widespread prominence through the German-language translations of Disney comics during the 1950’s. The translator, Erika Fuchs, used this form to describe sounds and actions of the characters (not unlike English crash! or pow!); eventually, these words evolved beyond onomatopoeic use, expanding to phrases like stare (starr) or dancing while sitting (sitzendtanz). Unlike onomatopoeias, these new forms followed a predictable pattern.

It should be noted that Teuber (1998, p. 8) describes the Inflektiv as a verb form that is non-inflected (German: nicht-flektiert); therefore, the German term Inflektiv should be translated into English as Uninflective. To avoid the confusion this causes, I shall use the alternative term, Erikativ.

Later:

Teuber (1998) argues convincingly that the Erikativ is a true verb form, as it has semantic and morphological restrictions that distinguish it from the freeform nature of interjections. Noting the common similarity between the Erikativ form and the verbal stem, he coins the term Inflektiv (‘uninflective’) to describe its lack of overt inflection.

The Erikativ is essentially the same as "actions" or "emotes" (WP) seen in most IRC channels and other chat rooms such as *dies*, *dances*, *rolls his eyes*, *coughs*, etc.

In comic lettering, emotes, when inserted within dialogue, are punctuated differently. These punctuations are called breath marks, crow's feet, cat's whiskers, or fireflies. I am unaware of any standard term that describes the "breath words" themselves.

1. For the first artistic display, I would suggest mass choreography. A mass is a name for a large group of people while choreography means a sequence of steps and movements in a staged dance performance. If you Google mass choreography there's a choreographer called Penny Jones who seems to specialize in this form of dance composition. Watch the Arbank, a Turkish bank company, TV commercial.

It's by pure fluke, I discovered who the choreographer is for this TV advert.

There is another dance term called tableau which means a pause during or at the end of a scene on stage when all the performers briefly freeze in position. The website about.com says

A ballet choreographer sometimes creates a striking tableau by arranging the dancers on stage in a unique formation. The dancers strike their individual poses and remain motionless and silent until the curtain is closed.

One renowned American musical choreographer during the 1930s was Busby Berkeley

Berkeley devised elaborate musical production numbers that often involved complex geometric patterns. Berkeley's works used large numbers of showgirls and props as fantasy elements in kaleidoscopic on-screen performances.

As a choreographer, Berkeley was less concerned with the terpsichorean skill of his chorus girls as he was with their ability to form themselves into attractive geometric patterns.

2. The term silhouette means a representation of someone or something showing the shape and outline only, typically colored in solid black.

The expression silhouette performance seems to encapsulate the art form presented by the BGT entertainers Attraction.