Passwords following Migration Assistant

Question

Hi folks
I have read a lot about Migration Assistant and Keychain, but nothing that addresses my needs.
I recently used Migration Assistant to move my old Mac Pro stuff after I had already begun using my new MacBook Pro.  I now have two user accounts on the MacBook - let's call them NewMacBookPro (the default MacBook user account I had been using for a brief period) and OldMacPro (the user account I've lived within for a couple of years now). I would like to now delete one, and it would seem easier to delete NewMacBookPro because this account has none of my old email/bookmarks/application licenses etc.  However, the OldMacPro account is having some glitchy Keychain issues which I would like to fix before completely eradicating NewMacBookPro, which does not have these issues.
The issues I'd like to resolve:
1) Finder Admin password requests: Every time I try to delete a file in Finder I am expected to give the Admin password, even though both user accounts have Admin privileges. I have tested to see whether it was a matter of trying to delete files/apps from OldMacPro that were originally installed in NewMacBookPro, but it matters not.  If I want to delete anything in Finder on OldMacPro I need to enter the password every single time.  This problem does not occur at all in NewMacBookPro, even when I decide to delete an app that came over with OldMacPro.
2) Keychain access password requests: The first time I open the Safari, or Mail (and some others) applications in OldMacPro, I am prompted to submit my Keychain access password.  While this is only requested once, it is not requested at all if I open these programs in NewMacBookPro, and was never requested on the old Mac Pro. I don't mind entering the Kaychain password once per program if it is intentionally set up for security, but I made no such change and yet here it is... Why?
3) Starting Keychain from scratch: Basically I would like OldMacPro to implement Keychain in the way NewMacBookPro did by default, which is also the same way as it was implemented on the old Mac Pro by default.  I never changed the setting in either system, yet the migrated version now performs differently.  I would also prefer to delete all the Keychain content from OldMacPro and use instead the new Keychain content and settings from NewMacBookPro in order to start afresh with renewed control over what passwords are saved.  Can Keychains be transferred between account, or do I need to reset Keychain somehow.
OldMacPro had Snow Leopard fully updated so there should have been no OS discrepancies between the old Mac Pro and the new MacBook Pro. 
Thanks!

Answer 1

In a word, no.
One of the reasons is, your TM backups include a full copy of the version of OSX from your old Mac. It won't run on your new one. Even if they're fairly similar, some hardware is slightly different, with different requirements, etc., and no Mac will run a version of Leopard that's earlier than the Mac's build date.
You'll note that when you use +Enter Time Machine+ on your new Mac, you don't see the backups from the old one. But if you mount the old Sparse Bundle, then hold down the Option key while clicking the TM icon in your Menubar, the option changes to +Browse Other Time Machine Disks,+ which is badly worded, but will let you see them. So they're still there, and items can be recovered if you need them.
You best bet is probably to erase the TC via Airport Utility and let TM start fresh.
Or, to save some space on the TC, you could manually delete some backups, and/or the backups of your /System and /Library folders, via the TM interface, per the instructions in item 12 of teh +Frequently Asked Questions+ post at the top of this forum.
Then you'd have to "compact" the old sparse bundle (it doesn't do that automatically), via a Terminal command:
hdiutil compact (hit spacebar, drag Sparse Bundle to Terminal window, press return)
But note that TM will not delete old backups from the old machine as it makes new ones for your new Mac; you'll have to do that manually.