You need to delete it. There never has been a rule about air entries. There was a rule about land entries but that’s been scrapped now too. If you qualify for visa exempt you’ll get 60 days on entry by land sea or air.
There isn’t a set limit on the number of times you can enter. It’s at the discretion of the immigration officer.
The business visa is generally a Non B visa. You can get a work permit on a non O if married to a Thai national or have Thai kids but I’m assuming you mean the Non B.
For most companies trying to get a Non B in country is nigh on impossible. Many can’t provide the vast amount of paperwork immigration would need to issue one. And I mean vast.
Usually it’s way easier to have the person visit a nearby consulate and apply there (or via the evisa system where applicable - you have to be in the country of the consulate you are applying to regardless that you are using the evisa system).
I seen loads of questions from people asking what to answer on the DTV forums. “Do I put flights for 180 days out” or similar so I’d assume it does ask for something like that. I’ve not applied for one nor walked through the steps to do so so I can’t be sure.