Learn English – If it has a common name, what’s a big water bottle called

As a native speaker, I wonder: is the problem with the water, or with the bottle?

That said, a few expressions come to mind. The first one is the most direct:

You might not want to drink from that bottle; Ann already had her mouth on it.

The second is more of a euphemism than a scientific fact:

Don't drink from that bottle – it has germs.

(We don't know for a fact that the water has any contaminants, but the word germs is often used to refer to unseen microorganisms that could spread disease, particularly in informal speech.)

Because the concern is mainly with someone else drinking from the bottle, you could also say:

Be careful! That may have someone's backwash in it.

TFD labels this definition of backwash as "informal", while the Urban Dictionary says:

Backwash is often created inadvertently or unintentionally when liquid escapes the mouth during the process of drinking .. When multiple people drink from the same container, there will usually be some amount of backwash put back into the container.

As a footnote, the adjective for drinkable water is potable, though anyone who would deem bottled water as non-potable simply because someone else drank from the bottle is probably using extreme hyperbole, or else is an overly sensative germaphobe.

One problem is that, even if English has a word with the same meaning, that word would not indicate the same group of activities.  Many native English speakers would not consider vending or busking to be pseudo-jobs.  Street-vending provides convenience in addition to the offered goods.  Busking allows a performer to practice his or her craft in addition to exhibiting small-scale entertainment.  Even the guy wearing a sandwich board and distributing fliers is participating in the legitimate business of advertising. 

Granted, I doubt that most people would say that clergymen benefit the economy.  However, I wouldn't even want to consider discussing in a public forum whether clergymen benefit society -- religion can be a contentious and controversial topic, where I live. 

All that being said, there is a word in English that you may want to consider for your purpose.  The last two concrete examples that you've given are fortune-telling and professional mourning.  I'm not very familiar with professional mourning.  As an American, I find that such a thing doesn't happen in my culture.  However, I am familiar with excessively expensive funerals, with coffins that cost too much and burial plots that cost too much and wakes & memorial services that cost too much.  I'm also somewhat familiar with fortune-telling, card reading and tea leaf reading and palm reading and, of course, those that claim an inexplicable and inexorable psychic connection with the dead. 

One word that describes both those activities is "scam".  A scam is a way to gain money without providing equal value.  Many (but not all) scams are illegal.  Even those scams which are legal are never prestigious.  The economy does not benefit from a scam, and society views any scam as distasteful. 

A person who gets his or her primary income from a scam is a scam artist. 

It is entirely possible that, in your culture and your locale, a visible majority of street vendors are scam artists, in sharp contrast with the obvious social and economic value that many street vendors offer in my culture and locale. 

If you and I can agree that many fortune-tellers take money without providing value (to either the customer or to society), then there's a good chance that "scam" is the word you want.