Few thoughts on my choises for far save tanks:

H!Ilyana forma :

Pros -I can give her 2 merges; -can be a good duo Lif counter; I can use my free forma without spending orbs; -she has slick fighter so she's going to be immune to debuffs; -she has blue gift + sturdy stance 3 atm but I prefer foddering to her dd4 + H!Sophia's weapon.

Cons -I need to give her dd4 (I have an extra Caineghis); -she's weak to green tomes and bows; -she can be slightly weak to physical units considering her innate lowish def; she's going to get doubled by everything; -weak to dazzling skills; -if I ever stop using her I can't use her fodder for someone else.

Armor Fjorm:

Pros: -base kit is good enough; -immune to dazzling skills; -disables enemies' follow-up attack which makes her more tanky; -has stupid level of damage reduction and her prf special is immune to deadeye type of skills; -if I summon her I get that trait thing and a celestial stone as well; -I can give her dd4 so she can disable enemies debuffs (although she loses guard and extra speed from her native stance); -if I ever get tired of her she can still be good fodder.

Cons: -she is still weak to impacts skills; -she's green and inflicts physical damage so she's going to have a difficult time killing duo Lif; -I need to use orbs to get her and I kinda need to save them in order to get some units I like later on; -I don't care too much about Fjorm as a characters; -the other units on the banner don't interest me at all; -despite having the nfu fighter she can still be doubled by other faster units; she's not immune to debuffs (unless she runs slick fighter instead of her native one but it looks like a downgrade generally).

Conclusion: Fjorm is basically more consistent as a far save unit with all that damage reduction, nfu fighter and dazzling immunity but requires more investment, while Ilyana is less consistent but cheaper. I actually think Fjorm can have trouble killing few units since her build is focused on reducing as much damage as possible while with Ilyana I think I would run iceberg or ruptured sky. I don't know what to do as I have 154 orbs (+few from story mode). I'm conflicted honestly.