Massif Press infringement: Do not use your Mod to create standalone Lancer products unrelated to Lancer Tactics...
Is this meant to be 'recreate'? Because it seems like porting (for example) the entirety of Solstice Rain would be illegal without written permission - although the Lancer Third Party License is remarkably vague about what counts as a 'mechanic' and thus preauthorized to use for derivative works - but as-written it sounds like you're just not allowed to... use the LT mod database as storage space for tabletop-only homebrew?
Third-party IP: Is the lack of carveout for if you genuinely have the rights a tone thing? I'm not expecting any major publishers to want to let people mod their giant robots into LT - though it's not impossible that, like, Super Robot Wars has a permissive license for their original mechs - but mecha TRPGs are a popular genre on itch.io, and I suspect the list of modders who'd like to port mechs from a game they published to LT is nonzero.