- Minions are generally 2-3 levels higher than the monster they're based on. Presumably, this is because something like a bugbear shouldn't be conisdered a minion until a certain level is reached.
I am not sure this is a pattern.
- Minions have slightly higher defenses than the main monster, generally +2 to each defense. Since their defense is the only barrier to them falling down, presumably they require a more "solid" hit to really count.
This is because the minions you are looking at are higher level than the regular. This is not a minion feature.
Let's look at the level 8 soldiers from MM
Hobgoblin Warrior Level 8 Minion
Medium natural humanoid XP 88
Initiative +8 Senses Perception +6; low-light vision
HP 1: a missed attack never damages a minion.
AC 22 (24 with phalanx soldier); Fortitude 20, Reflex 18, Will 18
Hobgoblin Hand of Bane Level 8 Elite Soldier
Medium natural humanoid XP 700
Initiative +9 Senses Perception +8; low-light vision
HP 184; Bloodied 92; see also Bane’s blessing
AC 26; Fortitude 24, Reflex 22, Will 23
(Note that the hobgoblin above is elite, so withdraw 2 from 3 defenses before comparing)
Shadar-Kai Warrior Level 8 Soldier
Medium shadow humanoid XP 350
Initiative +11 Senses Perception +6; low-light vision
HP 86; Bloodied 43
AC 24; Fortitude 19, Reflex 20, Will 17
Speed 5; see also shadow jaunt
Angel of Valor Level 8 Soldier
Medium immortal humanoid (angel) XP 350
Initiative +10 Senses Perception +6
Angelic Presence Attacks against the angel of valor take a –2
penalty until the angel is bloodied.
HP 88; Bloodied 44
AC 24; Fortitude 22, Reflex 20, Will 19
Rot Scarab Swarm Level 8 Soldier
Medium shadow beast (swarm) XP 350
Initiative +9 Senses Perception +7; darkvision
HP 88; Bloodied 44
AC 22; Fortitude 21, Reflex 21, Will 19
As you will notice, both the defenses and AC seem to fall within the normal range of level. Minions do tend to have slightly lower stats the equal level monsters, but the difference is not huge.
So, basically, what I am saying is that you can take any humanoid that you want, change the hit points to 1, shave 3/4 of the XP, remove all but one or two attacks, and set the damage to almost a minimum and you have yourself a brand new minion. You might want to consider shaving 1 or 2 off the defenses, but basically, you are already there.
Hope it helped.