1. Removal of trailing year. You can add a comma to the $strstr check. It has to be in single quotes: ','
I've added it to the main one you want below.
$if($strstr(%path%,'://'),$cut(%title%,$sub($if3($strstr(%title%, - 19),$strstr(%title%, - 20),$strstr(%title%, -19),$strstr(%title%, -20),$strstr(%title%, 19),$strstr(%title%, 20),$strstr(%title%,',' 19),$strstr(%title%,',' 20),$strstr(%title%, 19),$strstr(%title%, 20),$strstr(%title%, '('19),$strstr(%title%, '('20),$strstr(%title%, '['19),$strstr(%title%, '['20)),1)),%title%)
2. Removal of radio station name. Seeing as you are using m-TAGS, it should be straightforward to use a custom_tag. Call it what you like. It may be easier to JUST add the custom_tag to the problematical radio streams you want to run the code for. Set it's value to say 1. Then the code simply checks for the presence of the tag. It shouldn't require anything else to check if it's a radio stream. So you can try something like:
$if(%custom_tag%,$trim($right(%album artist%,$sub($len(%album artist%),$strstr(%album artist%,|)))),%album artist%)