Why did the Women's Bathroom only say Jules until Leah Kerns joined the team? It makes sense if Jules is the only female S.R.U. member, but we know for a fact that Donna Sabine joined the team on a temporary basis, then joined Team Three, then ended up leading Team Three. Is there a bathroom just for Team One? Does Donna have a bathroom on a different floor with Donna on it now that she's (hypothetically) the only female member on Team Three? What about Kira and Winnie? Where do they get dressed at? Is Team One the only team that has locker rooms/showers in the Barn? We saw other teams working out in the Barn in "Haunting the Barn", so what gives?
Most likely, each team has their own staging area, which would be a logical way to avoid tripping all over each other, and occasionally uses each other's facilities when maintenance or something similar is taking place.
In "The Other Lane", Ed's brother Roy had stolen $100,000 from the police evidence locker. In a real life situation, Roy would not only go to prison but won't be trusted as a cop again after pulling off police misconduct even if it was to help bring down a gunrunner. So why did Ed say he'll put in a good word for Roy?
5x05 was a plot that could have been solved fast if not for Canada's gun laws. The boyfriend of the victim follows the Villain of the Week, a Serial Killer, and manages to cut him off. The villain gets out of the car and charges the boyfriend, stabbing him. If he were allowed to own a firearm, the boyfriend could have blown him away the second the villain got out of the car. Result: rescued girl and dead serial killer.
Logical fallacy: the assumption is that if guns are easier to get, the victim would be saved because the bystander would be armed. In reality, the killer would likely also be armed. And guns are not difficult to get in Canada, they're just somewhat more difficult than the US, and tracked much more easily.
Second logical fallacy: This entire scenario is based on one specific individual (the boyfriend) having a gun on him or in his car, one that he is supposedly unable to buy because of Canada's gun laws. But even in countries where gun ownership is less regulated, there are plenty of people who make the personal choice not to carry a gun despite the fact that they would be permitted to do so. Canada could have the loosest gun laws in the world and that still wouldn't guarantee that this particular person would have one.
Third logical fallacy: Your scenario leans into Possession Implies Mastery rather heavily. Just having the gun does not mean the boyfriend was a crack shot with it, and even if he is it does not mean he is sufficently trained or cool-headed enough to do the right thing in a life or death situation (his recklessly attempting to attack the serial killer, in spite of warnings from SRU 1, would point to him possessing neither). Had he engaged the serial killer with a firearm, he would be just as likely, if not more so, to hit innocent bystanders or even his girlfriend as he would his intended target.
Truth be told, this Canadian series is pretty clear in its position on the American Badass Bystander fantasy. In episodes like Grounded and Eyes In, civilians (and insufficiently trained cowboy cops, as seen in episodes like Unconditional Love) who play hero only manage to put lives in danger, including their own. If they had the episode play out as the op suggests, it would run afoul of one of Flashpoints main thematic lessons; Leave These Things To The Professionals.
In "Severed Ties," the mother was never told she wasn't going to regain custody of her children until she was well out of prison and turned over a newleaf. Why wasn't she informed sooner? It could had solved a lot of heartbreak and gave her more time to process it.
Why does the Joker have green hair, red lips, and white skin. This one's origin story is not a chemical bath, so why keep the similar appearance? Unless, of course, it was done to surprise the reader when their identity is revealed, but there's still no explanation for anything but the smile.
It's possible like the Joker in the original timeline, she first became the leader of a group of crooks, donning the mantle of the Red Hood, and a heist at the Ace Chemicals (or Axis Chemicals) went bad, which results in the green hair, red lips, and white skin.
You don't necessarily need a chemical bath, just makeup will suffice (as Ledger and Leto proved). The bleached skin could come from a chemical bath at most, or she might have gotten paler skin over what happened.
How is it that things that pre-date Barry's mother's death (JSA) and things occurring off planet (events of Abin Sur's death) are changed?
The fact that Barry's mom was saved wasn't the issue, it was that he caused a paradox while inside the Speed Force, which is linked to time. The changes essentially rippled outward into the past and future, from Earth to the stars.
Also, not to nitpick (1. because I could just be misunderstanding, and 2. because it's completely beside the point of your question), but are you suggesting that Abin Sur died and passed on his ring to Hal Jordan before Nora Allen died, which happened while Barry (Hal's contemporary, who debuted as the Flash a full three years before Abin Sur died) was still a child?