Removing of the accents can be done directly in the rename template. To remove valid characters you have to do some configuration.

When you force the encoding to ASCII or Latin 1 in a rename template, character folding is applied. This means you can create an F replacement character set, add your special characters and simple set the encoding to Force Latin-1 or ASCII in the rename template.

In Preferences - Rename Templates use the context menu to Create a set with the Default Fold Characters. Then do a Set as Fold Character Set. You can then add whatever characters you like to the set itself. The to field can be empty.

For more information look at the help for Preferences - Replacements and/or search for Fold Characters Substitutions via Yate>Search Help.

The above method lets you do it entirely in the rename template. You can alternately do it in an action by copying the title to a track variable, making whatever changes you'd line and then use a rename template which uses the same track variable.