renaming it to z_fresnel_mod.pk4 seems to work without issues, and also avoids the (to me) undesirable shuffling of the original tdm_base01.pk4 back and forth from the backup whenever the mod is enabled/disabled by Generic Mod Enabler.
disabled in St Alban 1
vs enabled in St Alban 1, so it's clearly working.
EDIT: when renamed to z_fresnel_mod.kp4, it loads after and thus conflicts with @snatcher's Core Essentials due to the presence of default.cfg in the mod root which overrides Snatcher's loot count assignment (F3). i can't see any reason for a default.cfg file to be included in the fresnel mod, so it should probably be removed.
there are likely to be other mod conflicts with this z_ load order, since it's a complete copy/paste of the entire contents of the default tdm_base01.pk4, plus @nbohr1more's edits.
the ideal solution would be to package it in aaa_fresnel_mod.pk4 (so that it loads after the default game data, but before all other mods, which I think is the intention), *and* only include the files that are changed by the mod, which would then cleanly override the defaults.
hope this isn't too much work