Is Nothing part of the All?

Let's see ... ALL = the set of all elements that are something. Therefore the answer is no.

I think Sartre's "Being and Nothingness" reflects HIS difficulty with finding some purpose to his life - his seeing life as "nothing" in spite of his "being". He was, of course wrong since his choosing to write about it (is this not a "purpose"?) WAS his being and it was not "nothingness". All too often, IMO, philosophers take a position that is internally contradictory - but I must add that human language and our capacity to understand may prevent us from NOT doing this.

Yep; as, the nothing is the space between the All.

Without the nothing, everything would be All stuck together, and that would be most inconvenient.

It's all or nothing. You make the call.

Only as a mental concept. 'No-thing-ness' cannot have inherent existence in the universe outside of the mind's imagination. There is only ever 'something', rather than 'no-thing', because energy and matter cannot be created or destroyed, only made to change form, which would suggest that existence is 'eternal' and 'uncaused', without "beginning" and "end". That may be news to some people, but to others, how can it be any other way?

To have all it is to have everything but to have nothing is to have not one thing, empty air.

more like its shadow or echo

No. It's part ot the paradox it creates

Actually a body is not nothing until it lives. Spiritually a body is nothing without spirits. Spirits are separate elements. A human being is not a single spirit. A human being during his/her life time is living with many spirits which have joined one by one since birth. They are knowledge, skills, feelings, emotions, interests and everything. Even thoughts are not your own. For example, when you want to take a decision on a subject, one after another the spirits think and you just listen, choose or reject the ideas which they transmit to your mind through your brain in the form of thoughts. Brain is just a media to connect the spirits to your mind. A mind is just a computer's mind. After the destruction of a computer completely you will not get it's mind. The same is the case with the human beings. Soul is nothing but an energy needed for the functionality of a body. It is not a spirit or anything else. All human beings are just robots made of flesh and bones and toys of the spirits for their games.

Spirits want to put everything particularly their sins on bodies, so that they think they can escape. It seems they always fear to some higher forces may be their superiors. They think that their sins may go with the human bodies. There is no afterlife to humans. No one lives in any form after death but humans must face the consequences of their sins until they live on this earth.

"All" without details is not reproduced, Illusion.

All in the empty wallet is nothing.

"All" = "every thing"; an idea is some thing: a "light blue unicorn" is an idea; "nothing" is an idea, etc. Therefore, the idea-word "nothing" is part of the "All." However, "Nothing" is the similar "trap" that Jean-Paul Sartre explicated: "Being and Nothingness" ("L'Etre et le neant") is a false polarization (i.e., equivocation). Firstly, "Being" for Sartre is "existing," as J-P claimed "there is no God;" secondly, when Jean-Paul Capitalizes "being and nothing," that = "existing and no existing." However, what does exist for Sartre is atom energy-based: we are "useless passions" and hell is being with other people (i.e., their 'looks' at you as 'the Other'; btw, 'other' is more correct--the correct use of Capitalization indicates the 'I and Thou,' wherein the 'Other' is the Godman as 'One Mind Soul'-Realization;' nb Nietzsche's semi-secularized Overman). Sartre simply misappropriated the Deific Capitalization convention, as a fallacy of equivocation. An honest, agnostic discussion re Deific capitalization: "we have no evidence of God, so we do not capitalize, and we note that Deific Capitalization indicates a Soul-based Knowing, or simply a Truth-claim by those who are assuming God Is, but who do not have God-realization, but simply Faith."

Even as Nietzsche sought his Over-manhood, after suffering the tragic loss of his beloved Pastor father, as marx despised his Rabbi-tradition father, as Camus grew up without his father, so too Jean-Paul at age two lost his father. (While J-P did have his mom's dad's influence--he was a classically-oriented Schweitzer (Jean-Paul's mom was the first cousin of Dr. Albert Schweitzer), the absence of a father in many a philosopher's life has implications for their subsequent Socratic search for happiness (a la unhappy marriage: unhappy family of origin). Cf Russell, who at two lost his mom, and at four lost his dad.))

It may be worth noting that the father, especially after the child attains to 7 and beyond (and when the dreamy alpha-wave-processing is replaced by beta-processing), supplies a kind of support for the inner child joy, love, security, etc., experienced by the little child and its loving mother--which transition and fatherly support then promotes Childlike abilities to engage and solve deficit-needs ---> being-cognition/self-actualization https://en.wikipedia.org/wiki/Maslow's_hierarchy_o... , which is one reason Wittgenstein counseled his philosophy grad students to learn real work...paralleling his awareness that most (he might aver all) philosophy is resolvable per "language-gaming."

Thus, Socrates' notion that happily-married men (and women) need not do philosophy (apparently in-sight in love is wisdom, wise dominion, harmony), but unhappily married folk well turn to philosophy (as search for happiness, being-cognition), is also by analogy applicable to dysfunctional family life and deficit-cognition (all philosophy is not based in dysfunctionality, and is not resolved by Maslow's being-cognition; Popper and Plato would affirm that insightful wisdom provides guidance re framing issues).

Sometimes the Capitalization of "Being" and "Nothing" is a "nothing burger."