Capital will be a min of THB 1mill and 2 thais per foreigner. Your employer needs to submit 2017 closing of account, last 3 months SSO paid for Thais, last 3 months of PND1 if they are paying taxes too. A simple CV will do. Based on marriage to a Thai.
Go quickly and pay THB 2,000 fine, get a stamp in the passport for the fine but it won’t affect existing extension of stay and it won’t even have any effect on your new application for extension of stay the following year etc.
The good thing about having a non O based on marriage and work permit is that they are not tie up together. So even if you cancel your work permit, your stay in thailand depends on the non O or extension of stay based on marriage expiry instead.