The 500k Baht question is do you have that sum (or equivalent) and do you earn an enough income to support yourself in Thailand….if you do, the rest is just paperwork.
If your husband owns the business, have the HR/office manager “certify” the job is remote; depending on the embassy/consulate you apply at, you might need to align bank statements to prove this.
You need to go back to your Bangkok Bank home branch for almost any changes…..they need to compare your signature with their records that are only available at the home branch.