Yeah, looking at the stat topic, Cirno is actually horrible at resisting ID (the average PC in her game cuts ID by 54%. She cuts by 25%). Needless to say, I think it's seems far more likely that she's actually pushing that ID axe up to turn 1 (assuming I'm reading this right).
As noted above (restating it here to get it out of the wall of text), I interpret LoT status resistances here the same way I interpret FFX PC evasion, because the two work almost exactly the same way:
LoT Status: success rate = (Base Success Rate - (Resistance*3))%. Base Success Rate is always 100% except for one attack used by an optional maingame boss (unknown higher value) and the aftergame superboss (same unknown higher value, I believe).
FFX Evade: hit rate = (Base Hit Rate - Evasion)%. Base monster accuracy isn't documented unfortunately but I suspect somewhat strongly that for the majority of monsters it is similarly 100% or possibly lower, given how rarely Lulu gets hit in game.
That said I know you're one of the people who's harsh on FFX (and FE) evasion, and so your view on the ID resistance would be consistent at least regardless of how much I don't agree.
Also, while it's on my mind, status blocker possibilities. It should be noted that sufficiently harsh views on LoT equipment render all of it DL-illegal, but some people do allow FFX status blockers despite them being not storebought, so here's the relevant data for LoT and you can draw your own conclusions. PCs in LoT can equip 3 pieces of equipment, duplicates are okay.
It's worth noting that if there's any status blocker you consciously farm in-game, it's death, because of boss Yuyuko.
The careworthy blockers:
Poison Resistance Ring: Poison res +20, one in a chest, three enemies drop it at rates of 4% to 4.5%.
Para Resistance Ring: Paralyze res +20, one in a chest, two enemies drop it at 4%.
Yamabiko Necklace: Silence res +20, one in a chest, one enemy drops it at 5%.
Ring of Hades: Death res +20, two in a chest, seven enemies drop (four at 4%, three at 3%).
Ring of Faith: Debuff res +20, one in a chest, one guaranteed boss drop, one random enemy drop at 3%.
Wing Amulet: Silence res +12, also gives +12% speed and +48 wind affinity, one in a chest, one enemy drops it at 1%.
White Immortal Sake: Debuff res +10, also gives +16% HP/SP/MAG, one in a chest.
Tellina Shell Necklace: Death res +16, also gives +16% SP/MND and +48 spirit affinity, one in a chest, one enemy drops it at 2.5%.
Black Onyx: Poison/paralyze/silence res +6, also gives +24% HP and +4% recovery, one in a chest, four enemies drop it (two at 2%, two at 3%).
Persona 4 Glasses: Poison/debuff res +12, also gives +12% HP/SP/MAG/MND, two in chests.
Phial of Galadriel: All status res +6, also gives +16% all stats, two in chests.
Lance of Geios: Silence res +16, also gives +30% ATK and +50 wind/cold affinity, one in a chest, one enemy drops it at 1%.
Karen Device: All status res +12, also gives +48 all elemental affinities, one in a chest, one enemy on the final floor drops it at 1%.
Egg of Life: Poison res +16, also gives +30% HP/MND, +6% recovery, +50 nature/wind/spirit affinity, two in chests, one boss drops at 25.6%, one enemy drops at 1%.
Forbidden Tablet: Silence/death res +16, also gives +30% MAG, +4% recovery, +60 mystic affinity, one in a chest, one boss drops at 25.6%, two enemies drop it (one at 0.6%, one at 1%).
Ice Sword: Debuff res +14, also gives +36% ATK and +60 cold affinity, one in a chest.
Star of Elendil: All status res +8, also gives +20% all stats, three in chests, three bosses drop it (one guaranteed, one at 25.6%, one at 5%), one enemy drops at 1%.
Ribbon: All status res +24, one in a chest, one enemy on the final floor drops it at 0.7%.
Dairokutenmaou Armor: Debuff res +12, also gives +24% HP, +48% DEF, +60 fire affinity, one in a chest, two bosses drop it at 25.6%.
Shiva's Leather Boots: Paralyze/death res +15, also gives +48% ATK/DEF, +40% SPD, one in a chest.
King of Heart's Badge: Poison/paralyze res +16, also gives +40% HP, +48% ATK/DEF, +30% SPD, +6% recovery, one in a chest.
Shuttle Body: All status res +20, also gives +36% DEF/MND, one in a chest.
Longsword Ringil: Paralyze res +24, also gives +68% ATK, +88% SPD, +128 cold affinity, one in a chest.
Gold Cloth: All status res +12, also gives +30% HP/SP, +40% ATK/DEF/MAG/MND/SPD, +48 all elemental affinities, one in a chest.
Dewprism: Silence res +20, also gives +50% SP/MAG/MND, +80 fire/cold/wind/nature affinity, one in a chest.
Armads: Paralyze res +36, also gives +50% ATK, +144 wind affinity, dropped by one enemy on the final floor at 5% for the first drop and 1.5% thereafter.
For the record, I haven't tallied up the other statuses yet, but there are 15 guaranteed death resistance items by endgame: one +24, three +20, two +16, one +15, two +12, four +8, two +6. This is 199 total points of death protection. A theoretical party of 12 average PCs has 218.28 points of death protection, so add these figures together and you get 417.28, or every PC having 34.77 death protection once you average the blockers over the cast. (34 is immunity.)