Complex sentence: King Features actually owned the name all along, as Bluto had been originally created for the comic strip, but due to poor research, they failed to realize this and re-made him as Brutus to avoid copyright problems.
Split into simpler sentences: King Features actually owned the name, as Bluto had been originally created for the comic strip. Due to a lack of thorough research, they failed to realize this and reinvented him as Brutus to avoid supposed copyright problems.