Hey there:)
Those settings sound very good already.
Generally it depends on what you want to achieve with Blokada. Check the replys to this post for some ideas on what you could change for specific use cases:
For the selection of host lists in Blokada check this article:
Host lists and DNS are meant to be used settings, yes. You can experiment with DNS based on privacy or speed. Depends what you want to focus on;)
I am sorry, I don’t get the second question? There are already default settings used, usually you just need to tap the big button and everything will work (with default settings:))