Bound Hero Battle: Ephraim & Eirika

Guide: https://www.youtube.com/watch?v=n3yUDPVMhzs

Eldigan (40+1): Fury, Swordbreaker (!), Bonfire, Fortify Cav
Camus: Fury, Reposition, Moonbow, Goad Cav
Titania (40+1): Fury, Reposition (!), Iceberg, Hone Cav
Cecilia: Gronnraven+(!), Triangle Adept 3(!), Green Tomebreaker, Moonbow, Ward Cav

To life an attack from the ninja AND Green Mage-Cav my Cecilia needs the +3 HP and +2 Res from C-Rang-Support with yourself, maybe +Res-Cecilia can handle this without. Let get her the full boost off Titania and Eldigan and went to the point left of the destroyable wall, put Eldigan under her and Camus under him, Titania waits under the destroyable tile.
The ninja with Sword-Cav-Boost would attack Cecilia and only made (the unfortunate) Poison Strike-Damage and the Green Mage-Cave attacks her from above and bring her to very low HP.
Next turn, get Cecilia under Titania and destroy the wall to take off the green Mage with Titania, which has to take a hit from the Blue Mage, that means get (in my Skill-Set) only 6 Points Fury-Damage, thanks to Emerald Axe+. Meanwhile took Eldigan out of the Range of any unit and stay with Camus in the range of the damaged Ninja and end your turn.
The ninja runs into Camus an dies and the Blue Mage attacks Titania. Now Ephraim should be in your Range. Attack him with Cecilia, go down with Titania and do Reposition on Cecilia and take care, that only Titania ist in Ephraims range. End Turn.
Ephraim dies when he attacks Titania and now the Sword-Cav and Eirika (from the Top of the Map) is near enough to handle them without beeing scared, cause know you can OHKO Eirika with Eldigan, thanks to his Bonfire and Swordbreaker and can take out the Sword-Cav with Camus and his Moonbow, that should trigger.
Now wait for the Blue Mage and blew him away (my Cecilia can OHKO him with Boosts / Moonbow).

Finished! That was what I made in Infernal-Mode because Lunatic and Hard are way too easy with this Squad needing any specific plan.
(Hint: Maybe you have to take care in positioning your Heros right, to get needed Boosts at the right time, but I think everyone can do this easily, because there are not that much possibilities, because you never really left the bottom right corner)

i didn't know what i was doing but i cleared it on lunatic mode anyway

Lyn: Neutral IV's Brave Bow+, Reposition, Draconic
Gaze, Swift Sparrow 2, B Tomebraker 3, Hone
Cavalry, Any Seal with HP+3
Camus: Neutral IV's, Gradivus, Reposition, Moonbow,
Fury 3, Vantage 3, Threaten Spd 3, No Seal
Julia: HP+, Atk-, Naga, Swap, Draconic Aura,
Resistance +3, G Tomebraker 3, No Seal,
Partners with Lyn(B-Rank), Summoner
Support(C-Rank)
Olivia: Dance, Hone Atk 3(Everything else is pretty
much unneccessary)
Other IV's / Summoner and Partner Ranks might work as well.

Turn 1: Start off like this:
----L-C----
-J-O-------
Lyn moves left by 1, Camus moves right by 1
and breaks the wall, Olivia moves to where
the wall was, Julia stays where she is.

Turn 2: Lyn moves up by one and left by 2 and
kills the dagger, Olivia dances for Lyn, Lyn
moves left by 2 and repositions Olivia back
to where the wall was, Julia swaps with Lyn,
Camus stays where he is.

Turn 3: Julia finishes off the green mage, Lyn
repositions Julia, Camus repositions Lyn, Olivia
moves down by 2.

Turn 4: Camus moves up by 1 and kills Eirika, Olivia
dances for Camus, Camus moves down by 2
and reposizions Olivia, Julia moves right by 2,
Lyn stays where she is.

Turn 5: Camus moves left by 1 and up by 1 and kills
the sword-user, Lyn attacks Ephraim,
Julia moves left by 1 and finishes off Ephraim,
Olivia Dances for Lyn, Lyn moves left by 1 and
up by 1 and kills the blue mage.

And done! (Sorry if my english isn't perfect, it's my second language)

Hector - +Res, -HP - DC, Vantage 3, Fortify Armor, HP+3 seal, Bonfire, Pivot

Azura (+2) - +Def, -Atk - Fury 3, WoM3, Hone Atk 3, Breathe of Life 1 seal

Brave Lucina - +Atk, -Res - Sturdy Blow 3, Renewal 3, Drive Spd 2, Spur Def 1 seal, Reciprocal Aid, Aether

4 star Sheena (lol) - all that matters is she had Fortify Armor, Swap, QR1, and Squad Ace A 1 seal

Basically with this set up Hector baited and killed the ninja, blue mage, and green mage cav turn 1. Azura baited and killed the red cav turn 2, Azura baited Eirika turn 3, BLucina moved into Azura's spot turn 4 to block Eirika while Sheena moved next to BLucina which was in front of Ephraim so neither Ephraim nor Eirika could move to attack the opposite unit because they were next to each other so they were forced to attack the unit blocking their path. Then Swap Sheena with Hector to let Hector finish off Ephraim.