The Demolisher Agriculture tech is locked behind mining Small Demolisher Remains.
In the No Enemies mode, the tech is inaccessible, as Demolishers do not spawn.

This could be changed to either an Agricultural+Metallurgic Science Pack research, just giving the research automatically if 'No Enemies' is enabled, or having a Mod-Setting option.
Or maybe have the world-gen spawn a 'small-demolisher-corpse' near the Vulcanus landing site? (Probably more difficult)

A user-side workaround is to change the research trigger from mining a 'small-demolisher-corpse' to 'ashland-lichen-tree'
(<Modfolder>/demolisher-agriculture_1.0.0.zip/prototypes/demolisher-agriculture.lua - Line 390 )

While I get the concept here... the demolisher mod is an enemies mod, if your pupae spoil they spawn baby demolishers which are some tough enemies. I suppose I am unsure how no enemies works on places like Gleba where you need pentapod eggswhich spoil into enemies...