This infographic from our friends at Thai Visa Advice explains the difference in the processes as outlined by Brandon. I totally agree with him stay well clear of Poiphet. The Laos borders are more user-friendly than those with Cambodia.
Some of the visa run companies won't take you if you've had a "volunteer" visa as there's no guarantee you won't be "interviewed" at length, and they don't want any delays. Make sure you let the company know that you have one these
. Maintain your own control over the monthly transfers. Take your eye off the ball for one moment and you can rest assured there will be a stuff-up, and sadly Thai immigration are very anal about the monthly transfers.
"should have no issues" being the key phrase. Without knowing her full situation it's not possible to be 100%. She can try of course, and if it works it's all good. Very often people live in different countries to that of their nationality
Depends on which country you're flying to, as the check-in counters will need to see your passport to ensure you have the necessary visa and/or credentials to enter the country of destination