On this forum modding commercial console ports of the game is a bit of a no-no.
Even then you run into the issue where you can't just put the game on a sd card and expect to be able to change the files around so easily, and Switch modding isn't a big thing anyway unless you have an old version or something.
The most likely case of stuff like dynamic lightning and animated facepics in mods would be if someone did something like that in CSE2.
So basically no, there won't be modding support for the Switch version of the game.
Ngl, Cave Story Switch could've done fine without the extra water physics. I'm not too certain about the graphics, but hearing that splash when something other than Quote jumps into the water, that won't get annoying quickly.
Currently, mods are indeed possible on switch, but stick with modding the switch version personally, to yourself. Uploading switch mods is highly risky, and just not worth it. I'm currently the only person I know who has a modded switch with Cave Story+ mods.
Notes on switch modding as of current:
-TSC is un-encrypted, pretty much text files. You can edit them easily with a program like Notepad++ (Booster's Lab / Cave Editor will flip their shit if you try opening the TSC files for the switch version)
-The menus get really wonky when you mod. I have no idea how to fix this, but a lot of text is just replaced with StringTable::InvalidKey
-Maps must always be widescreen in order to look right. This room looks odd because I ported a 4:3 room for a mod I made a long time ago.
-Music modding is possible if you know how to replace oggs
-Graphic changing mods are possible if you know how to edit the pngs (and know what each file is)