As mentioned in the notice at the top of the forum, the forum is intended for user to user interaction rather that official support, bug reports or feature requests. For requests you can use the form on https://theme-fusion.com/contact-us/ or create a support ticket.
For your questions:
1. Yes, this is possible, however, having it in the source should not cause any issues and will be necessary for any non default values (although we will also be looking into that at some point). You can still override inline styles from a child theme without problem, you just need to make sure the CSS in your child theme has more specificity.
2. This depends on what exactly you are trying to dequeue. For standard WordPress dequeue please refer to the WordPress documentation. Note, for customisation like dequeuing CSS that is really the user’s responsibility. If you are not sure how to make certain changes, then it is not recommend to be doing such things. There also really shouldn’t be a need to dequeue any of the core CSS/JS files.