The reason why I never draw Empty with anyone but Applebloom is because:
1. she is a kid. Empty can't stand adults. it takes alot for him to accept an adult pony.
2. Applebloom seems to be the only one that can accept him himself fully. my reasoning being that she did with Zacora
3.Scootaloo seems to be someone that won't trust someone easily.
4. Sweetiebell would probably not be let by rarity near Everfree forest in the first place.
5. Its SSSOOOO CUUUUTE! XD