FE7 has a set of event codes to set and unset the unit state bitfields, namely UNCM and UNCR. FE8, oddly enough, has no "generic" unit state setter. There are a few event codes that set specific bits: INVIS/DISA sets bit 0x1, SET_ENDTURN sets 0x2, etc.
The following hack allows you to set/unset whatever bits are in memory slot 1, like so:
SETVAL 0x1 0x2
and that will set 0x2 (already moved) on Eirika.
You'll have to add the raws to EA. I recommend adding them to "Language Raws/Units/Change unit condition.txt". You can change the names if you'd like.
#Set the bits in memory slot 1 to the unit's condition word (+0xC in unit struct)
SET_CONDITION, 0x3427, 4, -game:FE8 -indexMode:8
Character, 2, 2
#Unset the bits in memory slot 1 to the unit's condition word (+0xC in unit struct)
UNSET_CONDITION, 0x3429, 4, -game:FE8 -indexMode:8
Character, 2, 2
And here's a list of the bits that we know so far:
0x00000001 Don't display standing map sprite
0x00000002 Greyed out/already moved
0x00000010 Rescuing someone
0x00000020 Is being rescued
0x00000040 Cantoing/already performed an action
0x00000080 Under a roof
0x00000100 Makes movement squares display over the map sprite, but is cleared when selecting a unit, so rather useless
0x00000200 Doesn't display map sprite in link arena if Hide Units is set to 'On'
0x00000400 Related to AI; not entirely sure what it's for
0x00000800 Riding a ballista
0x00001000 Drop last item
0x00002000 Metis Tome/Afa's Drops has been used
0x00004000 Solo animation 1
0x00008000 Solo animation 2
0x00010000 Something about not drawing map sprites?
0x00020000 Kind of unused
0x00040000 ^, see below
0x00080000 If this and either 0x00040000 0r 0x00020000 is set, activates a "super arena" with harder enemies and glitchy alternate text if you enter the arena
0x00200000 Was not deployed last chapter
0x00800000 Increase portrait index by 1
0x01000000 Makes the standing map sprite shake very quickly. Doesn't seem to be useful otherwise
0x02000000 Unit is unable to take part in chapter (can't select from prep screen)
0x08000000 Use link arena palette