Also other (later game) options such as ally swap, heroic leap etc

Spell is phase shift, I can also think of Ally swap or any other ability which allows jumping or teleporting, such as Assassin's reach, Smoke Bomb, Heroic leap, some duelist weapon abilities etc.

The option to input a seed is unlocked when you first win; on the character select screen you press the cogwheel and select the seed option

Sounds somewhat like a more tame (effects wise) version of the trinkets system Evan is working on atm

Other than that, I feel like it's unnecessary complexity

An interesting question, though I'd point out that the squares seem to be roughly character-height in size, and DnD characters walk noticeably faster than that

Also works for the 4 gold chests levitation rooms

Is it by any chance arcane resin-ed to +3?

Do you mean the 2 alchemy rooms? It's not that exceedingly rare, the one with a cauldron in the center is a bonus room

Treating plants and webs as traps does sound like a somewhat reasonable default. Even when as a Warden I want to step on a plant I don't rely on the pathfinding to go through the plant.

Right, in that case yes they will help, but for the later pricks their rather low blocking (compared to upgraded plate armor for example) won't do much. Shielding potions are a much safer alternative

The "upgraded RC" is presumably curse infusion, and you loose the levels if you uncurse the item. Still might be worth it to reroll the curse, I don't know if you need to uncurse first

Well I guess I'm no one then. As a Huntress main who heavily utilizes grass, I very much avoid blazing, (and unstable because blazing) and love me some chilling