@ Mr Frog - Telekenesis limitation is sensible but fails to take into account that it's been shown that they can and will use thier magic in an offensive manner if needed. And they can teleport, however I'll leave that as posing them same risks as using gates (Think warp spiders. Weaker ones or particularly unskilled ones run the risk of never reaching thier destination.) They have been implied as being the least physically imposing/capable as well.
Pegasi I'd prefer to view as having a type of magic to even permit thier flight they have no control over, and for our purposes traded weather control for durability.
Overall and literal magic involved can be totally possible, since Necromancy is itself magic. It's just science outpaced magic and therefore mages not of necromantic groups or of species out side the Equus species as sort of like those lone practitoners, being few and far between. But god help you if you have to fight those nonpony/necromancer mages, as they can and will slap the shit of small armies.
ALso: I took a nap, that's why it seems you're the only on online. And question not my ability to make a logical reason for something or a handwave thereof; I have two setting that run off pure unadulterated bullshit, which require them quite frequently. For example,in place of OG!Frog, Talvieno can make use of a kill team sent after Vanya, disguised as Spearbreakers infantry. The common dorf sees someone running from soldiers, they'll assume it's just some criminal.
This is also known as: Splint, Legendary +5 Master of !!BULLSHIT!!. And now I shall proceed to beg for my life and ask that if you're gonna kill me, aim for the head and make it quick.