Maybe Arcueid and the other characters of Tsukihime/Melty Blood may appear in the cast of Fate/Grand Order as Servants and this new story as will be supervised by Kinono Nasu, then it is even within the chronological timeline of Type-Moon's history.
The basic form of Arcueid as Servant of the Berserker class would be that seen in Fate/EXTRA, its advanced form it would be his normal self and its final shape would be your most powerful form as Archetype: Earth.