I explain each of these enhancements below

Previously entered Searches (Filter tool) - http://support.solidexplorer.pl/responses/previously-entered-searches-filter-tool

A simple method of SE 2.0 remembering the last Filter search query and displaying it next time you use Filter or displaying it as grayed-out text that is ready to be re-used

Lock filtered results - http://support.solidexplorer.pl/responses/lock-filter-a-new-idea

Locking the filtered results would be slightly different than 'remembering previous Filter entry'. Locking filter means to me that the actual Filtered list view is locked or remains as a display even after entering and exiting folder directories that are part of filtered results.

Text Highlight the words of Filtered search results - http://support.solidexplorer.pl/responses/text-highlight-the-words-of-filtered-search-results

So I think for Solid Explorer 2.0, the whole row of the file's column in List view should get highlighted with the same accent color :)