What puzzles me is that people go on a trip and while staying there in Savannakhet start asking question. Common sense would be to prepare all well before. May be I am old fashioned. I hope our OP will get the visa.
First your husband need to be with you. Than you need to present documents as Original and signed copy. Prepare Red Ribbon of Marriage, your passport and your work permit. A letter from you confirming that you still married and live together. Last is a letter from your Employer confirming you are still employed. That should cover the requirement.
that the IO will stop you and not let you leave. You have to think the other way around, they want you to prove that you really studied up to the date you decide to leave the country. Example you stopped study 15 October and decide to use the visa as origianl admitted like 7th December, than, in their eyes you overstayed since 15 October.
they do not get numbers, they have the paperwork in order and pass direct to the officer in that section. It's good for the officer too, all is double checked and correct beforehand.