Hi!
1. Here – Search performance
2. Well, there is post type filter available, that can be defined as a drop-down as well (under the Front-end Options -> Post type filters panel), but the post author will be displayed still.
Instead of that, you should try a custom code to remove the author from the result. Add this custom code to the functions.php in your theme/child theme directory (copy from line 3 only!). Before editing, please make sure to have a full site back-up just in case!