Can my husband apply for a Non O dependent visa after I receive my Non B Business Visa?

And they will need to apply outside Thailand.

Yes, visa-wise, IF your employer provides the necessary documents for him to apply for Non-O dependent on you.

But, it totally depends on the employer and your contract with them whether and when the employer would provide documents. You (or he) cannot apply for his visa on your own without paperwork from your employer.

Talk with your employer well in advance.