Having gone through this several times, you are exactly correct - especially in points 2 and 3. We always asked the older ones to help out with the new one in all situations - Could you please hand me the diaper, or could you please hand me the bottle, or would you like to give the bottle, or do you want to help bathe the baby..etc etc. When they have as much involvement as possible, they too begin to connect with the new addition and will want to be the big brother or big sister. However, the sharing part will always be a problem. No matter how much the like/love their younger sibling - "That's mine" will always be the toddler mantra! Just keep working on the sharing thing.

One of the other things we always did, and still do, is each of us will have "mommy time" or "daddy time" with each of the kids where it is just us one-on-one.