
1) Actress Dolores 2) An Elvis 3) Anglicised Irish surname 4) Buck Privates co-star 5) Elvis of music 6) English-language education 7) Half a comedy team 8) Half of a classic comedy duo 9) MUD game 10) Radio Radio rocker 11) Singer Elvis 12) The other Elvis
Found on
https://www.crosswordclues.com/clue/costello

1) Lou
Found on
https://www.crosswordclues.com/clue/costello
[online game] Costello is an educational MUD — a text-based online role-playing game — designed for teaching English as a foreign or second language.{R|tesl-ej} It is offered online as a free service.{R|costello-online} Created in 1995,{R|costello-authors} it was innovative in its use of the MUD medium for EFL/ESL instruction,{R|cinii-m...
Found on
http://en.wikipedia.org/wiki/Costello_(online_game)

1891–1976, Irish political leader: prime minister of the Republic of Ireland 1948–51, 1954–57.
Found on
https://www.infoplease.com/dictionary/costello
No exact match found.