I previously held a Non B visa and work permit through my company. I got married last year and put the company on hold for about 10 months. I changed my visa to Non O but would now like to restart the business. Do I need to change to a Non B or can I get a work permit and still retain the Non O visa?

A Work Permit can be obtained with a Non Imm Visa based on marriage.

I suspect you may be talking about extensions of stay rather than actual visas but yes a work permit can be issued on a non immigrant O visa entry as well as a non immigrant B.

They will issue a WP as long as the non-O is based on marriage and not on retirement.

Are there any different tax implications being on a non O vs a B? Is there a minimum salary for a non O as there is on a B? It seems a non O for occasional part time work would be good if a minimum salary/tax was not the same as on a B.

They will issue a WP as long as the non-O is based on marriage and not on retirement.

A visa doesn't state the reason it was issued, only the visa class. That is why people who are still on there original entry should have no problems getting a WP on a non-O.

Only an extension of stay shows the reason for the extension and than one will have a problem getting a work permit.

Are there any different tax implications being on a non O vs a B? Is there a minimum salary for a non O as there is on a B? It seems a non O for occasional part time work would be good if a minimum salary/tax was not the same as on a B.

Your visa class has nothing to do with the ammount of taxes you have to pay.

Only your personal circumstances are taken into account.

The minimum requirement is more for an extension of stay and depends on your nationality and doesn't apply to certain jobs, like teaching, working for the government and members of the media.

But for an extension based on marriage the mimimum requirement is 40,000 a month OR 400,000 in the bank for at least 2 months. For based on working the minimum requirement is for most nationals of western countries 50,000 a month.