Speculation:
They had the reveal planned for this week for whatever this project was(assuming it's Shenmue IV) and were building up the hype as subtly as they could, whilst also not commenting on any rumors or speculations.
My theory is Geoff Keighley got wind of it and said "Hey, there's no E3 and I'm hosting this big event in its place."
Wanting maximum exposure for both their fledgling publishing studio and to capitalize on the renewed interest in the IP after the animes conclusion, they accepted.
I think Yu's birthday happened to be a coincidence. I think they mean the week of June 10th.