@mirabilos oki, thanks! (i hope you don't mind me examining it) (also i'm just curious about what works and what doesn't, and made my thoughts public here, please don't take this as me pushing wayland to you)

to note, on my wayland setup compared to yours:
* i live in foot, minimal wayland-only terminal emulator (and supports sixel)
* all those apps listed should run on wayland (either natively, firefox, inkscape, or via Xwayland)
* no screen or tmux bc i make heavy use of my tiling window manager, but this is unrelated to GUIs
* bitmap fonts work perfectly IME (i use the IBM VGA font)
* Xresources indeed don't exist, every compositor or application has it's own config file
* XCompose and Xmodmap can be used, as wayland still uses xkbcommon for keyboard input (in a *weird* way internally, but it does), though you probably need to tell the compositor to load those files
(i do use compose myself for brazilian accented characters like ã, é)
* xlock can be replaced with any client that implements ext-session-lock
* xsel can be replaced with wl-clipboard¹ and primary and clipboard both are present (don't think secondary is though, i've never heard of it even when i used X11)
* there's a few tools that are similar to xdotool but their use are somewhat limited (mostly fake keypresses or clicks, but window management is limited)
* for xrandr you use the compositor's config, or, a tool like wl-randr²
* gpu support should be there but i don't know, depends on the intel driver mostly (and software rendering is an option on wlroots based compositors, idk about GNOME or KDE but i doubt)
* for X forwarding over ssh, waypipe exists and works wonders, never tested it across endianess though
* unsure what rdesktop is but sounds like vnc, vnc to non-wayland targets works as expected via XWayland, vnc to wayland targets, wayvnc³ exists

1: wl-clipboard depends on wlr-data-control, which is implemented by basically every wlroots compositor, and KDE, but not GNOME
2: wl-randr depends on wlr-output-management, which is implemented by basically every wlroots compositor, but not GNOME nor KDE
3: wayvnc requires the target to implement some specific protocols

so, mostly there. those protocols caveats are being ironed out, wlr-* protocols being proposed as official protocols and seeing wider adoption-- but if you're like me and is going to use a minimal wm, it's likely wlroots based or supports the wlroots protocols, because it's kinda impossible to have it minimal without those protocols.