I would say that you were lucky that only your HDMI port and the ethernet adapter got fried. Your four port extender should be OK as all it does is spread the connections of one USB cable across four but if you have any reservations about it I would suggest that you just chuck it and get another. Amazon UK is selling this Sabrent expander for £11 today, not overly expensive.
To test your flash drive check its properties to see that it is showing its rated capacity then write some data to it and see if you can read it back. If you can then it is good to go.
Edited by Chris Cosgrove, Today, 04:25 AM.
Moved from Win 10 Suupport to External Hardware