Both your Ike and Boyd are 1,4 points below their Str average
but it's not that big a problem. Both Ike and Boyd have good
str growths so don't worry they will come around.
The miracle you lost is not such a big deal.
It is helpful but it's not that important.
Use both Rhys and Mist, two healers are
always better than one.
The earth affinity is the best when it comes
to avoid so if you pair two characters of this
affinity you will have two great dodgetanks.
Also wind,dark and thunder affinities give
an avoid bonus so if you want big avoid
try pairing characters of these affinities.
Don't worry PoR is not a very difficult game
even in hard mode.
It's definetely easier than both FE7's HHM and
FE6's hard mode.