1. Savings, the more the better. It's better if both of you can be the sponsors and it doesn't matter if he is the ONLY account holder.
2. It refers to the T-4 form that you will get from your employer at the end of each year. However, for visitor visa, this one is not necessary if you can present your pay slips for the past 6 months, which I think you can.
3. Either way is fine, but my personal experience is that it takes much less time if somebody can submit it for them in person.