Does redistribution mean publicly placing a windows .exe using the BSD licensed library for users to download on a website(free and commercial)
Yes, that is redistribution.
sharing the exe with friends (free and commercial)
That also is redistribution.
Can redistribution even mean just packaging your project into a exe because you are like rearranging the files into one executable??
No, that sounds more like compilation. If you're not conveying the program to another party, whatever you are doing, it's not redistribution.
Are we required to include the license in readable form in an exe in the project application itself or just in the project folder like a readme?
The 3BSD licence says that "Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer" and that "Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution".
If you're distributing an executable (without accompanying source) then it seems to me that including the required text "in the project folder like a readme" would suffice.
What if people forget to include the notices for some libraries? Is it required for copyright owners to try to get the user to correct it first or you can pay fines or something at any time?
If you redistribute without honouring the terms of the licence you are violating the original rightsholder's copyright. The consequences of that are entirely a function of your local copyright laws. In practice, an aware rightsholder will often ask you to correct your error before taking things further, but they don't have to give you that opportunity.