CHOOSING A RPG MAKER

unklmnky69
1. the ability to down size resolutions, i.e., I want my overworld tiles and sprites to be 16x16, town tiles 16x16 and sprites to be 16x24 (like FF NES/SNES) and ideally change screen resolutions as well to more closely mirror FF NES/SNES

You likely already know that tile and sprites are already these sizes in 2k3.

2. the ability to have party sizes of up to 7 or more characters

I do not think this can be done with the regular 2k3 engine. I've never tried to make a party this size since good balance is already hard enough. Maybe with the Maniacs Patch. It can probably be done in VX Ace or MZ with scripting and plugins, but then you have the issue of the tile and sprite sizes. With MV, you can do with the TileD plugin, but when I tried this, it made it hard to set a good, matching resolution.

3. custom, sprite-based attacks/magic/skills (not particle) again, think FF NES/SNES

This can be done on any RPG Maker, I'm not sure about MZ, since it forces you to use a particle based animation creator unrelated to MZ in order to make attack animations.

4. larger battle sprites, maybe 36x48, not sure yet

2k and 2k3 allows a battler size as large as 48x48. There should be no upper limit (within reason) to how large combat sprites can be in XP and onward.

5. ability to have individual weapon sprites for battle screen, not just when attacking, but during idle animations as well

More difficult in some RM engines than in others, but should be possible in all of them.

6. ability to have characters automatically level up in the times that they aren't in the party, so that when they rejoin the story/party, their level is similar to that of characters that have been grinding

Possible in all engines. Easier to do in later engines with third party scripts and plugins. I like to do this, too, in my games. I say easier for later engines, but it's actually not that hard to do in any engine.

7. ability to have enemy sprites on the dungeon/overworld screens, ideally a system like zelda 2 (NES) where the sprites wander around, and when you touch the battle starts, but at a minimum, bosses standing still and boss fights starting after dialogue when you interact with them

Easily done in any engine.

I used RPGM 2003 back in the day, and I would use it again, but I'm not sure about the party size, and I'm not happy with the square arrangement on the battle screen, I'd much rather it look like FF NES/SNES did, in a line.

You can change the battle screen layout to look any way you want on all engines, including 2k3. It only looks like that because of the isometric backgrounds that the RTP uses.

No matter what engine you choose, a bit of what you're trying to do isn't standard in any of them. Your desire for sprite resolution and tile size makes 2k and 2k3 perfect, but is going to be a pain in the ass in later engines to get it to look right. Conversely, weapon sprites on the battle screen can be pretty easily done with third party scripts in later engines, but will be a pain in the butt to pull off in 2k or 2k3, but should be doable using the Maniacs Patch. If you don't want to use the Maniacs Patch, it's not going to be easy to do. But it can be done, even if you have to draw every battler with every possible weapon in duplicate battle sheets and change the character battlers as you change weapons.

I think a seven member party for battle is going to be tough to pull off in 2k or 2k3. I know that it's possible, but not without some serious engine breaking.

For overall aesthetic and how you clearly want the game to look, I'm leaning hard on 2k or 2k3 for you. But I am generally biased in their favor.

Oh! Just having a party that size? Not having battles that size? That's much easier. I don't know if 2k and 2k3 allow that in their standard code, but it wouldn't take much to break that in the common events. In VX Ace and higher that is actually something that the standard system allows.