yes, first time no problem for Non O marriage, they just not want that you keep going every 5 month and apply for Non O and than the 60day extension. But things have calmed down a bit so they might relax on that.
Yesterday the applications, first timers got approved in Vientiane. Repeat or second course I can not confirm. I would observe the one year rule, but better you go to FB page of Royal Thai Embassy Vientiane and send your question, there is a very nice person that replies within hours.
there is a difference between rejected at the window and told no and given the option to apply another Visa. You can try somewhere else in such case. All Consulates still issue Non Ed Visa if all is OK. But in some cases, after a long history of Tourist visa, than for example Savannakhet or HCMC will issue the sticker, but VOID it. In this case you have little or no chance to apply somewhere else in the region. With that I close comments. Reflect your situation and apply for the correct visa. BTW, all newcomers to Thailand are usually granted ED visas, as this is a creditable situation.