I understand your argument but I propose it carries an inherent flaw. Try this: Faith is the process of making claims and holding opinions in the absence of knowledge. If something is known and/or understood, then we have knowledge and Faith is not required.
To claim that something is unknowable or unfathomable immediately negates any current or future knowledge. You are defining that Faith must be maintained because:
knowledge would supersede faith, questioning religious dogma is often defined as losing ones faith,
I may have "trust" in the process of gravity to act according to processes we have knowledge of, thus, there is no need for "faith" relative to gravity.
There is a deep difference between trust and faith. Faith is belief despite or contrary to evidence, whereas trust requires evidence to be maintained. People talk about "faith" in one's doctor or "faith" in one's friends, but I maintain it's really trust based upon their patterns of behavior. If your doctor botches an operation on a loved one or a friend fully betrays you, your "faith" is gone. What you had all along was trust, which they betrayed, which is why you no longer trust them.
With faith, you would continue to trust them no matter what they did to you.
That's why people have "faith" in an all-loving god
who wiped out most of humanity because they were a disappointment to him
and he will do it again
because he loves you
Now, as with my argument with Loki, we're simply splitting hairs on the definition of faith. The inherent flaw in your reasoning is as follows:
faith   /feɪθ/ Show Spelled[feyth] Show IPA
noun
1. confidence or trust in a person or thing: faith in another's ability.
2. belief that is not based on
proof: He had faith that the hypothesis would be substantiated by fact.
3. belief in God or in the doctrines or teachings of religion: the firm faith of the Pilgrims.
4. belief in anything, as a code of ethics, standards of merit, etc.: to be of the same faith with someone concerning honesty.
5. a system of religious belief: the Christian faith; the Jewish faith.
I'm sure your definitions were reached via some profound bit of reasoning, but nowhere in my understanding of faith (or apparently the online dictionary's) is the qualification that faith and evidence are mutually exclusive.
Even rational beliefs, in that they are beliefs absent undeniable
proof, are a form of faith.
Trust is faith.