I submitted Tues with the plan that the buses would have been on Monday BUT this week Mon was a public holiday so I hit the vans. If you go on a Tuesday will be quicker than my experience
No buddy, you only need a letter from your wife if going to HCMC. No proof of funds for the multi entry, but be aware with this visa you only get 90 days permission to stay each entry, but with a bounce at the end you will get 15 mths + 1 mth extension from this style of visa.