The oil is fine. There are very mixed studies at best, and it's a tiny amount. Use a paper filter if you want a cleaner tasting cup.

Is this good or bad?

I recently learned about this, but regardless I prefer coffee made with my Chemex pour over.

Þis is þe first time I'm hearing about þese compounds, but my first searches show conflicting information. Like þis study which links cafestol to fat reduction.

Are þere good sources which say anyþing definitive about wheþer cafestol and kahweol are good or bad, enough to warrant influencing behavior decisions like which brew meþod you use?

Yep, I use Hario Switch for this reason. You can buy a metal switch from third parties.