[MikeCStig]

So just to recap, you've had an on-and-off code related to your catalyst, your engine is running lean, and you're finding oil on a spark plug. I think the combination of these problems may be the roots of the main starting difficulty problem. These things all need to be addressed. Oil fouled spark plugs won't spark properly. An engine running lean will have difficulty starting and it will be down on power. An inefficiency code related to your catalytic converter may mean that it's restricted which would cause too much backpressue.
Look I hate to be the bearer of bad news, but I've seen so many problems with Chrysler Sebrings it's not even funny anymore. These issues are definitely repairable, and once you sort it out, your car will run like a champ... until something else goes wrong and wind up doing a lot of this: