Well, on a different note about Strange Fake (SPOILERS ABOUND! BEWARE ALL THOSE WHO READ!).
Edison is confirmed as True Berserker, as a lion/spider/robot hybrid (think Doc Ock with spider legs and a lion head). No idea if the Presidential Mystic Code support is applied here. True Caster appears to be Prelati (Male) summoned by Prelati (Female) (essentially self summoning as Prelati does body hopping to live longer like Orochimaru). A master called Sigma will transform into True Lancer due to his type of summoning and his current Servant/s is a group of random shadows/wraiths, who if given a proper class fall into Watcher (unknown details). Counter Force shenanigans are involved as Enkidu senses this oddity due to CF. Watcher can hardly do anything (limited to lifting spoons and such), speaks with a female voice and can transfrom Icarus, Ascelpius, Ahab and Orion, people it supposedly killed. The theme is people who tried/succeded in doing the impossible which was taboo and killed for it.
And at the end of Volume 3 True Archer and Berserker (Jack) get into a fight, which we don't know the conclusion of, but is hinted that TArcher might struggle as Berserker (Jack) is super strong against humans/Servants without Divinity.
So as of now, there are 13 Servants involved: 6 Fake Servants like Gilgamesh, Enkidu, Dumas and such (All classes except for Saber), who aren't actually supposed to be there, 6 True Servants like TArcher, TRider and so on, who were the actual Servants summoned for the war, and Richard, who is both True and Fake Saber (his summoning was supposed to start an event for those manipulating the whole war, but he met Ayaka and things went to shit).