Can H4 be rejected based on spouse's profession?

My H1B is approved for Oct 2016 to Sep 2017. I am married and my husband is a marine engineer.

I would like to take a H4 dependent visa for my husband. I have the following questions. Appreciate if you could clarify the same. Sorry for the long list of questions.

Are there any chance that H4 could be rejected for my husband because of his profession? He sails for six to 8 months and will be on leave for next 6 – 12 months.He has not sailed for past 18 months (he was at home) and if he gets the H4 visa, he is planning to stay with me in the US for a year and then will come back to India. Will Visa officer find a problem with this?What is the minimum duration that he has to be in the US for H4 not to get expired?Can he just obtain the visa now and join me later, say after 6 months?Can we book appointment for both of us together and if he is not able to make it to the interview will I have problems with my visa? Or is it ok if I reschedule the appointment for my husband alone?Is he allowed to work outside the US when he has the dependent visa?He already has C1D visa for his work and will that be a problem for him to obtain H4?If he gets h4 will there be a problem for his C1D visa?

Are there any chance that H4 could be rejected for my husband because of his profession? He sails for six to 8 months and will be on leave for next 6 – 12 months. No this should not be a problemHe has not sailed for past 18 months (he was at home) and if he gets the H4 visa, he is planning to stay with me in the US for a year and then will come back to India. Will Visa officer find a problem with this? NoWhat is the minimum duration that he has to be in the US for H4 not to get expired? There are no set limitsCan he just obtain the visa now and join me later, say after 6 months? Yes he canCan we book appointment for both of us together and if he is not able to make it to the interview will I have problems with my visa? Or is it ok if I reschedule the appointment for my husband alone? You should do it together, it is always the best option. But if you can’t, it does not matter.Is he allowed to work outside the US when he has the dependent visa? Yes - work is prohibited in the US or with a US registered company payroll.He already has C1D visa for his work and will that be a problem for him to obtain H4? No, it only strengthens the H-4 application.If he gets h4 will there be a problem for his C1D visa? No, the two visas have no conflict with each other.