To change the label for 'My Wish List' to 'wishlist' , go to vendor/magento/module-wishlist/i18n/your_language.csv (i think there will be en_us only) And change:
"My Wish List","My Wish List"
to
"My Wish List","wishlist"
I cant understand whatOkay, so if want to change as in the screenshot, goes to the same file and change this as you want with items.
"%1 items","%1 items"
to
"%1 items","%1"
This will implement the change that you want, also you have to do in the line before that is "1 item","1 item"and remove the second item if you want to remove in case that there is only 1 item in the cart.
If you make the site multilanguage, don't forget to make the correct translations of this or this will appear in the other languages.