Moving to Hanoi Between December and February 2016

Hey Guys, I am South African currently working in China and looking to move to Vietnam ( Hanoi ) in the next 2 to 3 months. I have a few questions i am hoping you guys can answer if you don't mind ?

Firstly some information about me :
I am White Male South African Native English speaker.
I have a Bachelors Degree and a Tefl Certificate.
I am currently in China on a 1 year Working Z-Visa.
South Africa is on the list of Preferred native speakers to teach English.
The Reason I am only making the move in the next 3 months is because i want to move with a descent amount of money so i don't have to jump into work straight away.
I plan on Staying in Vietnam for quite a while, possibly a few years.

My Questions :
1. Is the Vietnamese Dong still widely used ? If i come over can i convert majority of my money into VND or will i need majority in Dollars ? The reason i ask is because converting Chinese Yuan to VND I get far more out than if i convert to Dollars. Can i pay for day to day living in VND ?

2. In China i am teaching all ages, from 3 year olds to Varsity students. However, I would much rather prefer Middle school upwards ( 12 years and older ). Is there a lot of part time work in that age group, or is majority of the part time in the much younger students as it is in China ?

3. How easy is it to find part time work ? is it widely available as it is in China ? Here there is so much work I turn offers down on a weekly basis, they kind of harass you here and even beg at times... I plan to really just relax and lay back my first month in Vietnam and start working in the second month, So i will spend the first month looking for work, But i plan to fill my schedule with Part Time only, I am done working full time for schools.

4. Paypal : How well does paypal work in Vietnam ? For Example, in China I can use paypal to pay for things, but withdrawing from paypal to a bank is a nightmare, ( Direct withdrawal to Bank account is not supported in China ) the only way to do it is via wire transfer to a bank account, which means you pay $35 for withdrawal and you have to withdraw minimum of $150 and it takes 7 working days. The reason i ask about paypal is because i do some programming work on the side and i get paid via paypal, so i am curious about the withdrawal process in Vietnam. Some months it amounts to a significant amount, So having paypal function properly is quite important to me. I do plan on opening a bank account in Vietnam soon as I enter the country.

These are pretty much the questions I need answering at this point that i am unsure about, if i think of anything else I will add to the list, but if someone could address these for me I would be really grateful.