One of the many great things about AngelList is that they don't charge commissions. In the case of an AngelList syndicate, there is both a management fee and a carrying cost, but that is not deducted from what you raise but rather deducted from the investors' profit (if there is one).
The likelihood that you will be successful in raising $100k via AngelList on the other hand is quite low. While it would be a great place for you to find potential angel investors, I would advise against you using it to actively fundraise for such a small amount.
Happy to talk to you about AngelList and fundraising strategy in general.
AngelList does not take a cut of your raise. The exception is if you use "Invest online," where AngelList creates an LLC to pool multiple smaller investors into one. In this case you pay no fees, but your investors would ay a 10% carry to AngelList.
This depends upon the syndicate that you are a part of. As you have asked this question a long ago, lot of things have changed.