1. One of the rules in my tores (when I had stores, before I retired) was that you had to successfully replace 6 screens on junk phones before being allowed to work on a customer's phone. That usually took between 10 and 20 tries, depending on the person. So ...
2. No, I don't think you can do it successfully. You'll end up with a non-working phone, and have to pay a few hundred dollars for someone to fix your mistakes - then replace the screen. Which really wouldn't be worth it.
3. You can get the screen on eBay for about $30 but - as I said - I wouldn't do it if I were you. (I have the same problem with an S5 with a bad USB port - the screen has to come off that one to replace the port. At my age, I know I'm not going to be able to do it, and the cheapest price I've found to replace the port is $80. And I can buy a gently used S5 for $90 - so here I sit with a useless S5, charging the battery in an external charger when it runs low. [It's not my daily driver, so it doesn't matter. I'd sell it if it was worth buying - but it's not.])