Antillion and Murray aren't in the same Universe as Matthyse. There's NO fighter Rios has beaten that Matthyse wouldn't have also beaten. Matthyse would also destroy Abril.
Mathysse's power is legit. His punches are ridiculously hard. Rios has only fought 135 and Mathysse will probably ice him cold.
Maidana probably wouldn't happens since they are in the same gym. Rios will probably have the advantage of sparring with him though. That should give the 'internal' folks a chance to gauge where Rios fits in at 140 a bit.