Yes. But there's been many reports of airline staff asking to see your TDAC before allowing you to check-in to your flight. So you better have a plan B if that happens.
I don't care what other people tell you. It's not grey. This is how visas work. Embassies will not issue visas if you tell them your travel is not within 90 days. But once the visa is issued, it is valid until expiration date. Period. End of story. There is no system or mechanism to cancel a visa after that.
The official government website is your local Thai embassy. Each embassy sets their own requirements, so anything posted anywhere that is not the place processing your visa application is irrelevant.
You don't have one. Leave it blank like people have been doing for the last 2 years.
And ignore anything you read on the website you linked. It's from an agency that's just trying to drum up business for themselves and CONSTANTLY posts incorrect or outdated information.
There's no such thing as a "DTV card". It's not a membership program. It's a visa. And the pdf you received from the embassy is your visa. You need to print it and keep it with you for 5 years, and show it each time you enter Thailand.