Tenses in dependent clauses with conditionals

From wikipedia:

Apart from the special cases referred to in the sections above, many
other dependent clauses use a tense that might not logically be
expected – in particular the present tense is used when the reference
is to future time, and the past tense is used when the reference is to
a hypothetical situation (in other words, the form with will is
replaced by the present tense, and the form with would by the past
tense). This occurs in condition clauses (as mentioned above), in
clauses of time and place and in many relative clauses:

then they gave this example:

If we were that hungry, we would go into the first restaurant that we
saw. (simple past instead of simple conditional)

I’ll try to phrase my question the best I can.
If that rule didn’t exist (the one about changing the tense of a hypothetical situation to the past tense), would it be correct to say

If we were that hungry, we would go into the first restaurant that we would see

?, even though see isn’t the consequence or the result of the condition clause?, and would all the verbs in the main clause of a second conditional sentence use the simple conditional tense (would + root form of a verb)?.
wikipedia page (if the hyper link doesn’t work there’s another link at the end).

What about this example:

If A happened, then B would be (present) the case, so I say:

If A happened, I would know that B was/is the case.

which one to use from the above choices?, knowing that B has not been the case before and is not the case at the moment of speaking. If the answer is "was", is that because of what wikipedia said at the start of the question?. wikipedia page

Also, let’s consider this example: There was a test last Monday and I cheated on that test, so I tell a friend:

If the teacher found out, they would fail me.

and I also wanna tell my friend that the teacher might imply that they’ve found out about it and given me a fail grade already by winking, so I say:

If the teacher winked at me, that would mean they had failed me
already.

does the last sentence express what I want to express?, if not, how do I express that in english?

Another example:

If the teacher winked at me, I would know that they had failed me already

would the sentence above be correct even if at the moment of speaking the teacher hasn’t failed me yet?, or does the action (failed) have to be done by the moment of speaking in order for the sentence to be correct?. wikipedia page.

Also from wikipedia:

The use of present and past tenses without reference to present and
past time does not apply to all dependent clauses, however; if the
future time or hypothetical reference is expressed in the dependent
clause independently of the main clause, then a form with will or
would in a dependent clause is possible:

This is the man who will guide you through the mountains.

We entered a building where cowards would fear to tread.

I want to know what is meant by "if the future time or hypothetical reference is expressed in the dependent clause independently of the main clause, then a form with will or would in a dependent clause is possible.", and by "possible" do they mean whether to use will and would in dependent clauses or not is optional in that case?. wikipedia page

One last question: can’t the zero conditional talk about one instance?, maybe I want to say:

If I want to get a job, I’ll have to study a lot.

my intention isn’t to use the first conditional in the above example, because that would mean the condition concerns the future, I want the condition to talk about the present, because I may have more knowledge in the future than now. I also don’t want the sentence to express something that is always true, for the same reason, I may have more knowledge in the future that qualify me for a job. So, does the sentence above talk about one instance/case?, and does the condition talk about the present?, and is that what is meant by the paragraph below?, from wikipedia:

Contradiction between the zero and first conditional: There is a
problem when the condition refers to the present, but the consequence
to the future, as in these examples:

If you are young, you will like that book. (I do not know how old
you are.)

If you are already so good at it, you will be a master in one year.

If he is already here, you will find him.

Formally, every sentence above looks like the first conditional, with the condition
having future meaning,[5] which was not our intention. Generally,
context and auxiliary words like "already", "at present", etc.
sometimes are enough to inform us that the condition has present
meaning, but sometimes are not, which leads to ambiguity, for example:

If you do it now, you will not have to do it later. The word "now" can
be interpreted as "at present" or "in the immediate future". Hence,
the condition can refer both to the present and future.
wikipedia page.

An unrelated question, in this sentence:

I didn’t come back because I had thought that you were dead.

the verb were is simple past, not past perfect, does that mean we only use the past perfect tense when the action we want to transfer to or mention next happens before a past verb that we are at or mentioning currently? .

And what does relative clauses refer to?.

Sorry for the punctuation if it’s making it hard to read, I tried my best (:

First wikipedia page: https://en.wikipedia.org/wiki/Uses_of_English_verb_forms#Dependent_clauses

Second page: https://en.wikipedia.org/wiki/English_conditional_sentences#Mixed_conditional

I’ve posted this question on another site already, but it’s been 8 hours and I haven’t received any answers yet. I’ve gone over the question and found nothing that I consider a problem, so I’m assuming it’s not because of the question and posting it here because I really want an answer as fast as possible, sorry if it’s a problem.