It vary from consulate to consulate. Quick google search lead me to Vancouver consulate:
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When I did it in Montreal 6-7 years ago they didn't ask any proof of fund nor the other two things in red (hotel and round trip). I'm guessing that website are rarely updated. Best to call the Edmonton one if they have one.
A tourist visa always increase your chance by air, but it's no guaranteed especially in Bangkok airport. I recommend entering from Chiang Mai or Phuket, the % of denied is minimal compare to BKK.
The TM30 is not a requirement for an extension but some immigration offices will ask for it. It depends on where you apply for the extension. As I said above, avoiding confronting your landlord is always best. I don't understand why you still haven't called your nearest immigration office to ask. Either A) Your landlord is telling the truth so you could have avoided all the recent headaches, or B) Your landlord doesn't want to do it, so most likely is doing something shady or slightly illegal on the side. If it's this then I would just move out asap. You do not want to be seen as a snitch, stay away from potential problems.
Terrible advice so far. This group is getting too big for his own good so a lot of misinformation is spreading around. I would suggest that people who "do not know" avoid giving their 2 cents. To answer your question
there is no report of getting denied a border run-in-out of Laos, no matter the stamps in your passport (ed, volunteer, etc).
The clampdown on ed and volunteer visa is irrelevant to border runs. The dreaded volunteer visa does not allow you to get the Elite Visa. Both Ed and Volunteer might cause you issues coming in by air, especially from Bangkok airport. And, you might have an issue in Poipet (Cambodia), but this is the case since forever and is not specific to the recent clampdown. Laos was and still is an extremely easy country to border run from.
The agent most likely is doing a Cambodian border run so ofc they won't preach for the Laos border run. You have received pretty bad advice so far from people with zero knowledge nor real-life experience. Laos border run is extremely easy, even if your passport is full of stamps including the dreaded volunteer visa.