Can conflicting SKSE plugins contribute to a 'fatal error sans papyrus'?

Yes, absolutely. SKSE (Skyrim Script Extender) plugins, like native plugins, are loaded directly into the game's process. Conflicts between SKSE plugins, or between an SKSE plugin and a native plugin, can easily cause a 'fatal error sans papyrus'. Ensure your SKSE version is up-to-date and compatible with your game version and all installed plugins.