I would advise you not to send multiple e-mails as it is looked down upon. Sending the 1 or 2 you have already is fine (i.e. a thank you note and your answer elaboration/correction), but anything more could be looked upon as pestering/desperate. Ideally, communication is kept to an appropriate minimal to avoid disturbing the hiring manager and putting a negative connotation on your name while still keeping in touch.
Answering something wrong is not the end of the world in an interview and replying back to one of the incorrect answers you gave shows you thought about the issue, gave an answer upfront when requested, kept working on the issue, found the correct answer, and finally provided the correct answer. It is a good trait potentially as well as bad one (i.e. overthinks things even after making a decision on them). You do not want to be seen as rethinking ALL of your answers as then you come across as potentially incompetent or unable to "think on your feet".
Saying "I don't know" or "I have never come across that particular scenario" shows honesty and integrity in most situations. Most hiring managers are happy to hear the honest answer then an answer where the candidate "BS'ed" or stumbled his/her way through without admitting he/she doesn't know. If it is only a question or two then it is fine, but if it is a lot more then it shows you may not have the skills for the job (or that you require a lot of training). Keep in mind that technical questions upon which you should be proficient in should not receive an "I don't know" answer (i.e. an Accounting Manager candidate saying "I don't know how to prepare financial reports" is a red flag for the hiring manager).
A good strategy for questions where you do not know the answer but do not want to sound completely inept if the problem arose in the position is to phrase your answer like this:
That is an excellent question, however I have never come across that scenario in my experiences, but I can explain how my thought process works to handle it in this hypothetical scenario. First, I would do ABC. Second, I would do XYZ while making sure DEF is done. Finally, HIJ would be completed allowing for the successful resolution of the issue. That is how I would handle the issue if it came up.
This shows honesty and that you are thinking on your feet. This is the better answer then just saying "I do not know."