It turns out that the Boneyard reward cards are all average types which is fairer in my opinion as getting a bad type as a reward does not justify the hard work put in. It also seems like they will not be usable in this week's Yang Gui Fei Boneyard as the game is probably still at its early stage where more new players are joining. I predict the bordered reward cards will slowly be allowed for use (It is already stated in the Yang Gui Fei Cup announcements I believe) but probably the last tier Boneyard will include first.
Here are my guesses:
Amateur Boneyard (or whatever the first tier will be called)
- will have a low level requirement
- in the future, might include 5* restriction like GC, maybe only 3 maximum
Rookie Boneyard (or whatever middle tier will be called)
- in the future, possibly include using up to 3 silver bordered cards or remain at no bordered cards until Boneyard is expanded to 5 tiers.
Veteran Boneyard (or whatever the last tier will be called)
- I think this will definitely be introduced soon with 3 bordered cards allowed first and later update to 3 gold bordered cards possibly when Boneyard is 5 tiers
GC eventually expanded to 5 coliseums and with DC seemingly expanding fast and also on both iOS and Android, we might see it happening soon. This week's Yang Gui Fei cup has around 40% of people below level 9 at the moment of writing so there are probably many players that are still early in the game. The ideal spread of a 3 tier Boneyard IMO might be 30-40-30 (Low-middle-high).
Update: In addition, look out for Hunting Ground-limited Boneyard as well as Strain-limited Boneyard if DC was to follow in GC's "footsteps".