I noticed that if I go to mysite.com/wp-includes/ then it shows all the files in that folder and I would like to disable it (I think that it's a security vulnerability).
After searching online I found an easy solution (adding Options –Indexes in the .htaccess file) but I'm wondering if this may cause any problems with Wordpress or with Google indexing my website?
I use that (along with plenty other htaccess security measures) with all my WordPress sites:
I use:
Options All -Indexes
In my root .htaccess file and have never had issues with either WordPress or search crawlers.
I also have an additional .htaccess file in my /uploads directory for additional security precautions. Some of it may be overkill, so your mileage may vary.