As both an electrician and a also having just gone through a new service in our new home u can offer a little info. You can mount your meter on a pedestal if you don't want to put on your house but the location will have to be approved by utility company. Doing so has both pros and cons, you will be responsible for the cost of both labor and materials to construct the pedestal, you should also install a main disconnect that would allow you to break power from the pedestal to your main panel inside (which also has a main shutoff). As an extra bonus you could install a transfer switch at the pedestal that would allow you to safely plug in a generator during a power outage, chain the generator to the pedestal and enjoy a quieter experience because the generator isn't right outside your window. The last consideration is that you will be responsible for any of the cost associated with the underground conduit and wire between the pedestal and the house, depending on how far away from the utility company connection you may also have to incur additional cost for wiring and conduit. Best of luck.

OH, I missed the last paragraph of your mesage. That installation is illegal and unsafe not just for the generator, but I suspect also for the wiring to the 220/sunroom circuit. The generator hookup is NOT ALLOWED to rely on you having to manually turn breakers on and off in the right order (without an electric or manual interlock to enforce that) as well as you have a VERY VERY DANGEROUS situation that I bet that generator has 220V present on exposed prongs. Get an electrician with a CLUE immediately.

First thing to do is ask the PoCo if they have any installation requirements. They will trump all when it comes to the placement, wiring, and configuration of the meter. Frankly, I'm not sure exactly what you are proposing. Normally, you are not permitted more than one "service" in a structure. There are a few exceptions in the NEC, none would seem to apply for an EV meter. So, I'm going to start assuming that we're talking about a single service here. Yes, you are right that there six throw rule. If between the "main panel" and your "EV panel" you can shut off the power to the entire service with six handle throws or less, you can do this if the panels are located together. If they aren't colocated, you have a bunch of other problems. As for ground-to-neutral bonding. You must bond at the service disconnect so, in the above scenario, both panels would have the bond jumper. Now it is possible that your AHJ may permit the EV charging drop as a separate service. In that case, each one stands alone (you have a separate six throw rule for each one), and both definitely need be grounded. The another possibility is that the utility will say NO to your plans and mandate a single disconnect ahead of the taps for your existing service and the new EV meter.

Get a rattle can of Rustoleum from Home Depot. Just tape off the glass so they can read the usage numbers. You might have to touch it up every year or two because rust always returns. Give it a light sand to remove the loose stuff first and clean off the dust with paint thinner. They also sell chemicals that convert rust into another molecule. Apply the Rustoleum as the topcoat. https://www.rustoleum.com/product-catalog/consumer-brands/stops-rust-advanced/satin-protective-enamel-spray-paint