The consulates in Laos have said 3-6 months of bank statements but some people reporting using just 1.
The consulate in Vientiane told me 3-6 and some have said they provided 3 and one said 5.
So 3 sounds like a safe bet if you can swing that.
However, I would email the consulate and tell them exactly what your situation is,
I suspect if you work for a company and have an employment letter, it’s 3 months, if you work for yourself they may want 6, plus company registration, possibly even a tax return.
They specifically said the correct date when I asked them for the letter. They insisted they had to mail it to me and just saw the wonky date when it arrived.
I think it’s for some optional graduation ceremony but they shouldn’t have added that as part of the course time.
I’m guessing immigration can see that both the extension and course end date are in the same week and shouldn’t be an issue?
Curious if the 2 day processing meant you picked it up on the 2nd day after applying (so 3 days total in Laos) or was it 2 full days after applying so 4 days total?