Ok, First let me say I am new to this as well so please take what I say with a "grain of salt". With that said here is my stab at the answers to your questions:
1. I believe them to be accurate but remember each scouts various areas of expertise and as such ratings they give may be favored in those areas.
2. The only penalty I know of is that the original scout was under contract and that contract must still be honored so you will be paying for someone you will not be receiving benefit from.
3. I believe you should receive a message in your mailbox from him much like you do with free agents but I am not sure on this. The other thing you should check out is if you indeed want him to be the director of scouting I think you are going to have to manually assign him because I think the AI typically promotes the next highest level scout to be your new director of scouting.
Once again I am not sure of the accuracy of my answers, maybe one of the HOFs can comment or verify
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The only thing I am pretty sure of is there is no such thing as a dumb question
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P.S. If you put the topic of the question in the title it helps others who may be having the same problem.