No need to carry a physical copy of your license around. You literally print it from home so no random person outside the FCC is really going to know what it is or think it's actually official. If some rando does ask to see your license, they have zero legal authority, so tell them to pound sand. If you do run into an FCC field agent(not gonna happen), they know they can instantly look you up in the ULS to verify your license is legit.
I would print out labels with your call sign though and put them on the fronts of all your radios for a while to help you remember it/remind you to use it. As u/CC878CO said, at the beginning or end of a conversation, or at 15 minute intervals if they get long winded, is all you legally need. Repeater owners may require more.
As for grounding, the set screws on the lip mount should be plenty. To be sure, hook a test light up to battery + and check for ground on the large part of the NMO mount(without the coax connected to the radio). A solid ground on the radio itself is usually a bigger issue.
You also don't need such a long antenna. GMRS frequencies operate with a wavelength of around 65cm(25in) and an antenna longer than that doesn't really have any advantages unless it's a dipole. The Ghost antenna should work fine both on and off road. I run a 1/4 wave NMO on the roof of my Taco because it's less likely to get snagged off road and I have no issues with range. It also doesn't scream 'potentially expensive radio to steal'.
You can tune the longer antenna by loosening the set screw and changing its length, or if need be even removing the whip and trimming some material from its bottom. The Ghost antenna, not so much.
Lastly, you probably don't need ferrite beads if your power & ground are connected/routed properly. The big interference sources, mainly your alternator, are much better than they were 30+ years ago because manufacturers now need to keep electrical noise from screwing with all manner of sensor. That said, I still run them out of habit because they are cheap insurance.
I can’t speak to the quality of these bnc adapters but this is pretty much what you are looking for. Sometimes you can find better pricing on a whole bundle of adapters, but often there will be adapters you don’t need in the mix. You could also skip the bnc adapters and just use a “uhf female to sma female” but it’s not a quick connect/disconnect solution and you’d have to screw it on or off every time.
DHT Electronics 2pcs RF coaxial Coax Adapter SMA Female to BNC Female https://www.amazon.com/dp/B00CVQJRUA/ref=cm_sw_r_cp_api_glt_fabc_RFJFP2VX9Q8D1NMF2Y5N
DHT Electronics 2pcs RF coaxial coax adapter BNC male to UHF female SO-239 SO239 https://www.amazon.com/dp/B00CW5JT58/ref=cm_sw_r_cp_api_glt_fabc_6A39M3ZZ6CW01GZXZ3T3
DHT Electronics 2pcs RF coaxial Coax Adapter SMA Female to UHF Female SO-239 SO239 https://www.amazon.com/dp/B00CVQP7CW/ref=cm_sw_r_cp_api_glt_fabc_3TZTHW3CCP14BNFR67T2
Tram 1235 3 1/4" Magnet with NMO Mounting, 17ft Cable with PL-259, Gold https://www.amazon.com/dp/B01K4R31QS/ref=cm_sw_r_cp_api_glt_fabc_246GR1XPTTFDA0HQ28GP
1126-B Antenna Tram Black UHF 1/4 wave NMO Pre Tuned 410-490Mhz Antenna Motorola Kenwood Icom Vertex Blackbox HYT Hytera Mobile Radios https://www.amazon.com/dp/B00L9D2N6Q/ref=cm_sw_r_cp_api_glt_fabc_MZDCHZ51BPQ50YQ2AD1M
The midland ghost antenna really isn’t a good antenna for GMRS. Most, if not all, have a swr over 2:1 which is awful for an expensive and non tunable antenna from a brand that spends more on marketing to new GMRS users than R&D. If you value a small, compact and practically invisible antenna, look no further than the “Tram 1126-B”. It’s 6” tall, thinner than a pencil, costs less and is a perfect 1/4 wave match for GMRS having a swr of less than 1.2:1 in all examples I’ve come across. Less expensive and works far better. I pair mine with a nmo mag mount with coax run inside the vehicle. I have a proper mobile radio now, but this is how I ran my kg-805g prior and how I have friends and family run a quick setup in their vehicles while we’re traveling together. A speaker mic plugged into the HT makes it even easier to use and talk.
You can find the Tram 1126-B in black or silver