Hey sorry, been a bit busy lately. What makes you want an M2? They are arguably one of the hardest parrots you could own. They are a lot like having a U2 but magnified. Their demands are higher (emotionally), they are also more emotionally unstable than U2s. I know you rescue a lot

, which I LOVE! There are so many in rescues that need good homes

. I really don't see how they could be okay caged all day. I would suggest only having one if they could be in a situation where they were loose all day, on stands, aviary, bird room (they require a RIDICULOUS amount of mental stimulation). Or in the perfect world, if you could take the bird to work with you - that would be awesome. Honestly, I love my M2 but if she were to pass, I would never own another one. They are just to hard to keep happy.
As far as age: after they mature, IMPO, once that personality has set in - its there to stay. I think that with age, owners just get more used to it and adapt to the personality so it seems easier. I think over time its natural to get complacent about the routine.
Gender: Males are a handful. In the wild the male calls the shots. In captivity males can be quite aggressive. The males are known for killing the females in captivity, for no apparent reason. Something that doesn't happen in the wild. M2s just don't cope well with captivity. The females are by nature more submissive. A male should only be owned by a very experienced parrot owner. Always get DNA done if it hasn't been so that you know what your getting. My female has all physical male characteristics: smaller, dark (almost black) eyes, pubic bones are close together - DNA = female. My female is EXTREMELY submissive. She has never even tried to bite, however I almost had my lip taken off by a female someone else owned. So you still need to be careful with them. Females by nature don't usually 'attack' they are more of reaction bites. The males sometimes can set out on a rampage. Just be cautious with them and never let your guard down around them.
Breeding season in the US is from Nov-March. They can be difficult to handle during this time. Their more fussy, harder to please. Their focus is on breeding. I think that this does increase with age. IMPO this drive to breed becomes stronger as they get older. Usually have a lot more screaming during this time (any time their needs aren't being met, expect screaming).
Noise: I know your house is already loud but they are one of the loudest. When Rome is inside if she sounds off it is deafening. I read some where that their decibels hit up to the same as a 747 on take off, I believe this fact (and so do my neighbors up to a one mile radius around my house).
Moluccan Cockatoos - Hornbeam Aviary
Moluccan Cockatoo fact sheet