How do I apply for a Non O visa in Savanakhet for my family?

Hi, I need some advise - how to apply for Non O visa in Savanakhet?

I'm a teacher in Thailand, I'm going to convert my 60 days tourist visa into Non-B as soon as my school will prepare the documents.

I live with my husband and son - we are all EU citizens (they also have 60 days tourist visa now) and at the Immigration they said, that first I need to get my temporary Non B, next get the extension for 1 year, and after that I can apply to convert their visas into Non O at the Immigration office.

However I think it's gonna take too long, so as soon as I'll get my temporary Non B visa, I'm planning to go with family to Savanakhet to apply for temporary Non O in there, than just make an extension at the local immigration.

I did it before in Vientiane, but have no experience in Savanakhet. Does everyone know if:

1. Marriage Certificate and Birth certificate must be stamped by Embassy and Ministry of foregin affairs? (in Vientiane No such requirement)

2. Does my husband must give a bank statement and if yes - is there any particular amount to have?

Please help me if you can. I'm so worried to collect all the proper documents before going to Savanakhet.