Mushrooms growing in my seedling potting mix!

Ok I can hardly call it potting mix... it’s just straight leaf litter scooped from the lower layer of fallen pine needles. It’s way better than purchased potting mix too- compare the result of cheap store-bought potting mix in punnets to pure pine needle mulch grown in long planters, even though the shore-bought seeds were planted weeks earlier than the pine leaf litter. Even regular worm tea didn’t help them grow faster in ‘proper’ potting mix.

I can wait to put some of this stuff on my yard because i’m Knee-high in arborist tree mulch and need it to decompose as fast as I can.

That's a good sign.  I would leave it exactly as it is, just put the seed right on top of it, and sift a thin layer of soil on top to cover the seed.  Fungal dominated no-till seedling starter trays!

So you mean the fungus will help future seedlings grow even better than similar soil without fungus? That's pretty cool if it does.