I've done this in my Gen4.
The speakers in the Gen5 are as mention 6x9 in the doors.
Stock JBL speakers have a treble/mid high range frequency blocker in the front door speakers. It makes all mid/high range to the factory squawkers in the dash for better sound imaging. Dash speakers has a bass filter. If you also have the stock JBL, you can reuse the 6X9 speaker brackets by removing the speaker and removing the frequency blocker. I would consider reusing the frequency blocker if your not upgrading/bypassing the factory JBL amp AND upgrading with a 2 ohm speaker. If not, discard both and use what you want to use for this.
I'm positive the factory setup has it running in parallel. If your going to run tweeters and components, you're going to have to run it or somehow chop the factory wiring instead of running your own wires.
I'm not sure how well actual tweeters will do in the stock position due to it facing upwards toward the glass. The Gen4 was easier to do this since the tweeters were already in ideal place IMO. I ended up amping everything in my Gen4 and there was a noticeable difference even with the factory tweeters running with a pioneer crossover. Need to replace my 4channel amp with a 5channel one. My main goal was going to maintain the OEM look as much as possible.
Word of advice - if you are going with components, you will need an decent amp. With this much power, you would really really want to consider sound deadening. The Gen5s doors are large and doesn't have half the material in the doors like the Gen4's. If you want any good sound to come out from better speakers, focus on sound deadening first.
https://www.sounddeadenershowdown.com/