Unearthed Arcana are already a part of D&D Beyond, but they will only add UA that has player options and is currently "active." So only UA released this year, and if an official release is tied to them then the UA will be removed. For example, the races introduced by the new Ravnica book were released as UAs this year and were on DDB. Once Ravnica was released, the official races were added and the UA races were removed, including the Viashino, a UA race that was not officially released.
This doesn't affect those characters already built with removed UA content. They just can't be selected as options for new characters.
will we see the UAs added at any point?
Unearthed Arcana are already a part of D&D Beyond, but they will only add UA that has player options and is currently "active." So only UA released this year, and if an official release is tied to them then the UA will be removed. For example, the races introduced by the new Ravnica book were released as UAs this year and were on DDB. Once Ravnica was released, the official races were added and the UA races were removed, including the Viashino, a UA race that was not officially released.
This doesn't affect those characters already built with removed UA content. They just can't be selected as options for new characters.
where are they?
Do they have the last one (the one about ships)
Select Playtest in the character builder and you'll see the options appear.
There are no player options in the latest UA, far as I'm aware.