Can you walk me through a roof replacement claim process?

I understand the basics of this (I think) but have some additional questions.

Scenario: Our roof is 15+ years old. House is insured through Allstate. We just recently had a pretty bad hailstorm and I found a leak during/after the storm. Now the entire neighborhood is bombarded with predatory roof inspection companies and that whole deal. Yes, I know to do my research first and ensure that I pick a company that has good reviews and a long history in the area, and I think it may be time for me to start that process.

Question 1: Can I use any company I want? Do they have to be approved by Allstate prior to selecting them?

Question 2: Are the roofer and Allstate going to be "friends" or "foes" in this instance? Basically I'm wondering who is doing whats best for me versus what is best for them (yeah I know everyone will be doing whats best for themselves)? Is this all a collective effort, or will there be in-fighting over whats covered/not covered and will I be pulling my hair out playing middle man?

Question 3: How does the process work? This is what I am guessing:

A roofer inspects my roof, says "yep there is hail damage". They give me a quote for replacement. I present quote to insurance as a claim. Then insurance has their adjuster out to "verify" damage" and approve/deny claim? Then I either get the go ahead or don't?

Question 4: If it is approved by my insurance, how does payment take place? Does the roofer bill me or my insurance? Do I pay for the whole thing and get reimbursed by insurance minus deductible? Does insurance pay the roofer directly and I pay my deductible to insurance?

Question 5: My policy states in multiple areas - Deductible $17,382 Windstorm and Hail. So I am assuming I have to fork over at least $17k for a roof no matter what...? I believe at my previous house had some sort of declining coverage of my roof -- the older it got, the less % of value of the roof was covered....does that ring a bell with anyone? I don't see any language in my current policy that reads like this, but I'm wondering if there is a scenario where I would have to pay MORE than the listed $17k deductible.

Question 6: I currently receive a ~$620 discount for being claim free -- I'm assuming I can kiss this goodbye once I have a claim, correct? (I know its literally called that, just asking). Once I have filed a claim, does it "go away" after a certain amount of time? Is there a chance to get dropped by insurance after a single claim?

It seems like I have heard a lot of people over the years say something to the affect of " well as soon as we get a nasty hailstorm we are going to put in a claim for a new roof and have insurance replace it" saying it almost to the affect that they are getting a "free" new roof. Am I missing the point here? $17k is a HUGE amount of money to me and in no way is something I want to do. Is the only benefit that I'm not paying $30k or some other higher number for the actual replacement cost? Is my insurance pretty crappy if that is my deductible? It seems really high.