You are at risk of confusing tense with time here.
The simple present has a variety of uses, which include reference to habitual action ("I go to the club every Wednesday") and reference to future time ("I fly to Madrid next Saturday"). The simple past also has various uses, which include reference to past time (obviously), backshifted references to present time (e.g. in reported speech), and reference to hypotheticals (notably after if).
Would+infinitive is the conditional, which in some cases stands for the future-in-the-past, and would+perfect infinitive is the conditional perfect.
So, when you write:
Present/Future: If I were braver, I would tell her what I think. (Subjunctive / Future Simple)
"I will tell" is sometimes called the future simple, whereas "I would tell" is the conditional. So there is no future simple in this sentence.
As to whether "Present/Future" is a correct summary of the time, that is debatable too. Both halves of the sentence represent a hypothetical. It is not exactly clear whether "I would tell" refers to a hypothetical present or a hypothetical future.
In any case, this isn't a mixed conditional. This is a second conditional.
According to the British Council:
The second conditional is used to talk about ‘unreal’ or impossible things.
If I won a lot of money, I'd buy a big house in the country.
Where would you live if you could live anywhere in the world?
If you didn’t smoke so much, you'd feel a lot better.
You can see that the second conditional uses a past tense form in the if clause. (For the second example, could has to be regarded as the past of can. It is not expressing past time here, but neither are won and did.) And in the main clause the conditional (would) is used.
The same is true of this sentence, which therefore makes it a use of the second conditional.
If I were braver, I would tell her what I think.
The only difference is that you have used the subjunctive "were" instead of the simple past "was". But for every other verb there is no distinction between the subjunctive and the simple past*, and even for the verb "to be", many speakers would use "was" in this sentence. (*I am disregarding the mandative subjunctive here, as its form is different.)
The "won" in "if I won" and the "did" in "if I didn't" represent the same sort of unreal or hypothetical condition as the "were" in "if I were braver".
Your other two examples, though, are indeed the mixed conditional.
If he had worked harder last year, he would be vice president now.
If she hadn't had a panic attack yesterday, she would be going on vacation tomorrow.
According to the British Council:
In mixed conditional sentences the time in the ‘if’ clause is not the same as the time in the main clause.
If I’d won the competition I’d be going to Florida next week.
This sentence shows the future consequences of a past action.
In exactly the same way, your sentence
If he had worked harder last year, he would be vice president now
shows the present consequences of a past action, and your sentence
If she hadn't had a panic attack yesterday, she would be going on vacation tomorrow
shows the future consequences of a past action or past event.
However, to go from that to saying that "she would" is a future verb or even "future simple" is just too confusing terminologically. But there is an element of futureness to the conditional, which is why it is also known as the future-in-the-past. In effect, imagine you had this sentence talking about the present and the future (the first conditional):
If he works hard, he will be vice president.
When talking about the past, this conditional is backshifted to:
If he had worked hard, he would be vice president.
And if you had this first conditional (imaging yourself thinking this yesterday before the panic attack):
If she doesn't have a panic attack, she will be going on vacation.
When talking about the past, it's backshifted to:
If she hadn't had a panic attack, she would be going on vacation.
Finally, to take this sentence:
If they had really tried, they would be the winners.
The interpretation of "they would be the winners" as meaning "they aren't the winners" (present unreality) is more likely. I think the use of the conditional implies that we already know they're not the winners - which suggests that the outcome of the competition is already known. You are right, though, the conditional is often vague about exactly when the hypothetical outcome would take place. Going back to those second conditionals, if I say "If I were braver, I would tell her what I think", I am not actually specifying whether I would tell her right away or wait a while, although the most likely implication is that I would seize an early opportunity.
