1)Can I file H4 application since my hu*****and is currently in 7th year H1B extension?
-Yes. H4 duration is separated from H1 duration. That means you can get another at least six-year H4 duation besides H1 duration.
2)If H4 is not an option for me, what are other options? If I change to F1, can I get a new H1B later without leaving US? Should I keep F1 at least a year in order to get a new H1B?