If I transform a Steamwork pet with a built date and the gear gender symbol into another Steamwork species by using the schematics and a yunium key, will it lose the built date and turn genderless, or will it keep those features? The Steamwork part in the FAQs aren't really that clear on that part for me. Sorry if this question has been asked before ;)

There was a thread recently and someone confirmed that yes they would keep the gear gender. I don't know about the built date though

I can confirm that the built date and gear gender stay :) I changed my steamwork antlephore to a steamwork donadak a few days ago.

That are awesome news! And I thought I had to save up for the Miracle Potion II xD You made me happy! :D