Well thing is that the Mule does not split that brilliantly. It is usable, sure, but the thing is that low output humbuckers can easily sound very weak and thin when you take half of them out. Also I would like to know more abou the P90 you eye, cause those can easily be rather strong in output (but very open so they are brilliant) which might overpower the mule depending on what it is.
So a two part recomendation: If you go Mule I would look into series / parallel rather than splitting. That also provides SCish tones but it keeps more power and stays humcancelling. Really good sound. Alternativly you might want to look at the Vintage hot range, especially the Abraxas. That is somewhat of a hotter mule, so you get that PAF DNA with beefed up mids, more power, slightly mellower highend and better splittability. One step up from that would be the Crawler which splits brilliantly and loves bright guitars. It is listed as contemporary, but is really vintage hot imho. That is even fuller, warmer, has an insane growl, sounds great clean, and splits best out of all the BKPs.
