>any tricks that would filter out the That Guys with minimal effort
Not really.
>How do you get players to structure their applications?
A bullet point thing is fine. You want to ask for specific pieces of information. Their age, their gaming experience in general and with the system, if they are consistently available at the day and time of the game. I have also seen people ask questions like "Describe your character", "describe your ideal game", "what was the most fun thing that happened to you in a rpg". Those are good, too. It isn't only their answers, but how they answer, and also whether they are able to answer all the questions and actually give you the information you want, that you are looking for.
>What are some red flags?
If they are under 23 or so, and you are over that age, don't bother.
If their responses are rambling, filled with spelling and grammar errors, off topic, don't answer the actual questions, are weirdly short, go on forever, or are full of "lols" and "omgs", stay away. This sort of thing means they either don't pay attention to instructions, can't communicate clearly with other people, have limited attention spans, don't give a shit about your game, or all of the above.
If they start off asking you to change systems, game time, house rules, or setting, don't bother.
If they are heavily referencing anime, no. Unless you are also really into anime, I guess, in which case have at it, I suppose.
Then you will need to actually talk to people before you consider playing with them. Asking questions about the game, their characters, their expectations, and their views on various issues like alignment or whatever is important to your game is important. But equally important is just engaging them in conversation and getting to know them a bit. Usually, you can tell after ten minutes of talking to someone if you are going to just fucking hate them or if you will probably get along.