I have over 425,000 Marriott Reward points in 2 accounts. A few questions:

Can two accounts (husband and wife) still be combined. I have heard conflicting stories.

If I take the 425,000 level award, is AA the preferred airline, as it seems this can be maximized to 60,000 per traveller, for a total of 240,000 AA miles...is this the maximum for 4 tickets? Any tips for maximizing the amount of AA miles you can receive?

Under this award, you receive two (2) 10 night hotel certificates. Do these certificates have to be used for 10 days in a row, or can they be split--4 nights here, 6 nights here? Can they be used a different hotels? How long are the certificates good for?

Any help much appreciated!