Permanent address must be your home in New Zealand. I strongly advise against putting your Thai address for permanent residence. There is a section where they ask you to specifically write your address in Thailand which is supposed to be your "intended" address.
A sponsorship letter from an employer seems like a viable option for a case like this since your friend is not incorporated or freelancer but an employee. Sponsorship in immigration usually refers to either employers (for getting a work permit usually, so a bit of different scenario) or family. Best to email the embassy and ask for clarification. If you do not receive an answer within your acceptable timeline and can not provide any proof of the 500k, have your employer draft a sponsorship letter detailing their level of financial support to you.
It says that you should print it out or must print it out ? Let me know and I'll acknowledge my mistake.
Regarding phone, if you have lived long enough in Thailand, you should know that they use their phone more frequently than westerners and QR culture is much more developed there. They can for example withdraw money just with there phone and no bank card, something that has barely started in the West.
Embassy in Canada can take 1 business day and some embassies like France will take 20 business days. This is the range so far, not sure if somebody has seen longer posted time for an application filed correctly.
In Canada, client company usually send what we call an EFT confirmation that accountant require at the end of the year to reconcile. It is usually send by email as an attachment for proof of invoice payment. Again, I am not sure that it is necessary in our cases but I added this.