There are sensitive topics that would better be covered under anonymous status... You're in Thailand and people aren't joking with diffamation law. As well, for the ones who got annoyed just ignore it, that's very simple. You'll find out that a lot of misinformation is coming from both sides here. Always make your own research on other websites/forums, etc.
Congrats. And yes, follow the instructions and you'll get it. I don't understand why people are trying to do everything their own way and make it difficult...
Yes, in that case the person received a multiple entry right away from abroad. However, when renewing with immigration (after one year), you'll need to request for a multiple entry and most likely wait until the initial renewal is granted before applying for it at an extra fee.
You'll need to prove you're still in Vietnam... They want to see any proof with a very recent date like a purchase bill or others. You're the second person posting about it here. It's now getting stricter to make sure people remain in Vietnam until approved.
All these "anecdotes" don’t change much about the situation. Most visa holders make it through without any issues (as they are fulfilling their visas purposes), while some may be further questioned. The frequency of this can vary depending on crackdowns or the government’s intention to attract more visitors. It has always been this way, even before the DTV, and that’s exactly what immigration is there for.