A small flathead screwdriver helps tremendously with seating those in place.

415-445mm on 5.0.

For your use you would need a fork with suspension corrected geometry. Spork 1.2 does not have suspension corrected geometry. You’ll want an Enve or Wiskey fork, or perhaps another brand. We will offer a suspension corrected fork in the future.

The Traildonkey is a carbon fiber frameset. It is lighter than the Flaanimal, and perhaps a bit more racey.
The Flaanimal is similar in geometry to the TD but is heavier due to steel main construction. The Flaanimal does offer more tire clearance and better native singlespeed compatibility due to the sliding dropouts.
The bikes overlap 80-90% on a venn diagram.

Those product names were a bit confusing. I just corrected them. Standard 3k carbon is available to anyone. RTP is builder only.

Matte would definitely match best.