Alrighty, time to clear up some misconceptions about BP...
1. As far as BP recievers go, M-Sable does NOT outclass espeon, at all. It's offenses are actually quite lackluster since it lacks stored power, most notably it's hardwalled by chansey, even at +6, should you not invest in SPA or run something dumb like focus punch. Furthermore, Sableye is slow af, and fails to outspeed even positive natured base 100s at
+6. Most significantly, this means that sableye is outsped by mega gard, no matter how many boosts you accumulate. This means that mega gard can easily stop your sweep cold, which is unacceptable. As a defensive magic bouncer, Sableye is unmatched, but he is utter garbage as a BP sweeper and I would literally consider m-absol before considering him.
2. Latias, on the other hand, is well worth considering. If you manage to bait out most/all phasers and crippling status, you can easily go to town with a sweep. The biggest problem here is thundy, who can easily remove your speed advantage and make you considerably more vulnerable to being revenged. However, the only status effects that latias doesn't really care about are leech seed, regular poison, and burn. The only real team I know of that really fits that bill are rain offense teams and HO teams without sash loom or t-wave thundy (which are pretty much non-existent, courtesy of megamence). I feel like M-Latias will fair quite well on semistall and balanced teams looking for a wincon/wall in one (much like UU suicune), but I feel iffy on it's ability as a BP sweeper. It may make a decent backup sweeper, but then you run into problems of having way too many overlapping weaknesses.
Nice lol, but what sucks is that Latias doesn't get taunt to avoid getting phazed (I wanted to use taunt Lati to beat MegaBro, but I settled on something else). Scoli's biggest nightmares nowadays are Quagsire, Zapdos (if it gets in and roars it out w/o taking a rock slide), and above all skarmory (walls it, phases it out, defogs the hazards, and does a potential huge amount with Brave Bird).
3. Not even close. ID scoli simply does not care about non-haze quagsire, nor does espeon. Phasers are a pain, but most of the time scoli can still pass +2 def and +1 speed to espeon before getting phased out, which is often times enough to sweep. Furthermore, smart wobbuffet play can turn phasers into setup bait, as most phasers are carrying SR and will use it the first chance they get, making them total encore bait. Scolipede's biggest nightmares (at least for my team) are taunt roar tran (and skarm to a lesser extent), rain teams, thundy in general, manaphy and NPers.
It can also be pursuit trapped and walled entirely by dark types while being annihilated by u-turn spam and even outsped by alot of things. Sableye can still taunt if thats ever an issue and I still see the nonmega form to be just as viable since his main selling point was recover+burn spam.. even sub is a possibly, something espeon lacks the bulk and typing to abuse as good.
4. BP receiver espeon could hardly care less about being pursuit trapped, because once it has it's boosts, it's planning on staying until either it dies or your team does. In fact, espeon generally laughs at pursuit because it's so darn
weak. After 2 speed boosts, pretty much the only relevant thing that outspeeds it is sand rush excadrill (which, to be sure, is a pain). After 3, nothing that has any relevance will outspeed espeon. U-turn spam usually fails for the same reason, it's just not strong enough to break espeon at +4 or +6 defense. The reason why espeon isn't always running sub isn't that it lacks bulk, but it lacks the moveslots. It needs all of morning sun(to sustain the sweep), CM, coverage move (to not get walled by dark types), and stored power. It simply lacks the ability to ditch a moveslot for subs, as much as it would appreciate it.