What is the best way to use a 1-year multiple Non-Immigrant "B" Visa to procure a work permit? Can one get a 1-year work permit based on the visa, or will the labour department issue a work permit every three month?

Visa has nothing to do with work permit (other than having for the work permit to actually be issued) - that is issued for a specific job and most often for one year at a time regardless of your visa entry. You can use a multi entry visa as normal (exit/return for new 90 day stay) or extend at immigration if you qualify.

You can get 1 an one year WP based on your B-visa.

Just must show 2 Mbaht in company-capital and 4 employees.

If you're married to Thai only 1 Mbaht and 2 employee.