If you've watched my recent WR you may have noticed that I've managed to find a way to manipulate the rng. Here's how everything works.

to start out with you save and reset the game ~4 frames after saving(you have to do a hard reset, not just hit the reset button) and then hold 'C' until the screen fades to white. (A also works in most cases that c does, but will change the RNG) on this screen the RNG doesn't change unless you press a button, so you press left for 1-2 frames (this is the hardest part of my manip) release it and hold 'C' until the screen fades to white again. the RNG rolls even with out doing anything at the entrance so you need to hold up to move. from here the RNG doesn't roll unless you press a button again, so you're free to take as long as you need to move around to manipulate the RNG.

since there's a cycle of lag frames followed by a single non-lag frame when free-roaming around the dungeon you can do any input either buffered or unbuffered, although bonking into a wall has a much shorter animation then any of the other movements so I wouldn't suggest buffering it. different combinations of 'a' 'b' 'c' up down left right and start during non-lag frames will give you different RNG (Mode does nothing), but for simplicity I only used up, down, left, and right alone. an interesting thing I noticed later on is that if you do all the same movements but out of order you'll get the same RNG, so if you alternate left-right-left-right it'll be the same as right-left-right-left.

Battles: by holding A or C until all actions have been confirmed you can keep RNG consistent. you can also combine 'A' 'C' and Start, but I tried to avoid this unless difficult manipulation is needed, from what I remember this has to be buffered. but from there you have an entire round to mess around and swap to a different buffer. If you press the direction keys or 'B' it will cause a lag frame every other frame and no action will be confirmed, making anything but attacking the first group of enemies nearly impossible. (although I think there's 4 lag frames you can buffer when the curser moves, but that proved to be very difficult)

menu canceling can be used to manipulate the RNG. the cancel can be buffered or unbuffered and will have the same affect, as well as the movement afterward.

Searching can be used as well, but takes a lot longer. selecting search can't be buffered, because the confirmation will take a random number of non-lag frames to complete. movement after the search finishes must be buffered. this is the only way to open chests and keep the manip.

item usage: The item you're using has to be in the first slot to work (with out frame perfect inputs I suppose). After pressing right you'll have 3 frames to release it, then 'C' can be either buffered or unbuffered, as well as for selecting "use", then the character you select (I think this has to be hiro but I havn't tested it much) must be unbuffered, then selecting your item must be buffered. (by buffering the character, the number of frames it takes to use the item changes, and RNG rolls ever other frame in the item menu)

Healing: This is even easier, all you have to do is select magic (~2-3 lag frames) and hold confirm. This means unfortunately that you can only use heal with milo unless milo is dead, and only at the highest level, and you can only heal the first living character in your party. (usually hiro)

Stats: I'm not 100% sure how these affect it but here's what I've gathered. HP: won't affect RNG until you die. IQ: I have no idea what this affects Speed: Probably affects RNG if the turn order is changed. Luck: changes pretty much everything as far as I can tell, this seems to be the most important stat for RNG manips. Attack: Makes you do more damage, RNG will change if an enemy has enough health to survive a hit that should have killed it, or dies from a hit it should have survived. Defense: Makes you take less damage, same as hp, shouldn't affect rng unless you die.

I've noticed that wearing extra armor can change a miss into a 1 dmg hit, not sure exactly how this works, or if something similar happens with weapons.

None of these change when or what the first battle will be, which means if you find a way to get zero encounters you can do it at any level. However having a bigger party can increase the number of monsters in the battle.

Gold and name length don't seem to change anything at all.

In theory you could make a manip up until doppler, since you'd have to use the False Idol to fight him, and then as long as you don't gain any levels could be continued through the trail of wisdom.