I have a DBD registered company. I find it very hard keeping abreast of what it what, things that are needed for this that and the other. Just running the business takes all of my time, I have no inclination or spare capacity to put sticky labels on documents. . . I keep up to date PDF scans of everything (with Ingrish file names), useful for Paypal company accounts etc etc.
. . . but it sounds like you have the right idea i.e. someone you trust. In my case that's my wife and daughter, and my son when he's old enough.
You'll need the company registration document for pretty much everything. The company rubber stamp is a big deal in Thailand too. As you're just setting up, you might want to investigate the availability of your .co.th domain name (in Thailand only available to registered companies, emails from a .co.th domain go a long way towards credibility, where most SMEs still use Hotmail).