If we did't know how it would go and wanted to make it clear that it didn't have to go the same way it does now, we would say 'We will see how it will go'. Your sentence says something about (usually near) future when we don't expect drastic changes. It goes as it goes all the time and we will check how it goes.
Let's say it's about a current project at hand and we've just started on it. It does not "go as it goes all the time"(it has just begun) nor it is a universal truth/fact. But in the future we would like to check on it and that's why we would say "we'll see how our project goes (then)".
All of your original sentences are correct.
"We will see how it will go"
is not a good English sentence.
We say, "We'll see how it goes."
For the second clause, we use the present tense. Whether it refers to the present, or the future depends on the context.
I don't think you can swim across this river, but try it and we'll see how you go.
The first half obviously refers to the speaker's opinion of his current ability, and the second half obviously refers to an indefinite time in the future - perhaps immediately, perhaps not.
I don't think he can pass this test. But he has four weeks to study for it, so we'll see how he goes.
It should be readily apparent what time sequence is being referred to. The speaker is basing an opinion on the present (and past), but the test of this opinion will not occur for another four weeks.
After the test:
I don't think he would/will have passed the test, but after it's marked, we'll see how he went.