I don't think it would hurt. It helps if she is employed and they don't think she is coming into the country for sex work. So if you can prove she has a job here or is independently self-sufficient or that you have enough to cover her all of her expenses and travel plus medical costs etc. then that will work out in your favor.
I don't know. But I would say take your police report with your passport to an agency first and explain the situation. Or just wait for the new passport to arrive
First off, congrats on your baby on the way! I would say if you are looking to minimize costs for your business then you get married and apply for a spousal visa. Or do what Greenwald suggested and do Thai Elite.