. I can personally tell you this is 100% correct as I have done 5 consecutive marriage extensions. They don't care where it came from as long as it's in your personal account and is the minimum balance for 2 calendar months prior to applying.
. You can work on a spouse visa( with permit). You can't on a retirement visa. Also need to be 50+ for retirement visa. Good luck finding work here as a 50+ foreigner nowadays.