12 April 1989: death of Gerald Flood, who played Kamelion in 1983 and 1984, and also King John in The King’s Demons (1983)
ii) broadcast anniversaries
12 April 1969: broadcast of sixth episode of The Space Pirates. Caven is defeated and captured; the Space Pirates are neutralised.
12 April 1975: broadcast of sixth episode of Genesis of the Daleks. The Daleks take over the bunker, killing everyone including (apparently) Davros; but the Thals bury them for centuries.
12 April 2003: webcast of “No Child of Earth, part 3”, tenth episode of Death Comes to Time.
Here via who_daily.
Regarding people playing themselves, Alex MacIntosh (Day of the Daleks) was a real newsreader. According to Wikipedia he often made cameo appearances in dramas playing newsreaders and journalists. You could potentially count The Beatles too (The Chase), if you see that as acting (the footage was not filmed specially for Doctor Who).
I agree about the amount of Time War plot threads here. As an existing fan who had got a bit bored with what I saw at the time as continuity overload in the spin-offs, I hoped at the time that this marked a radically new take on the continuity, where old favourites like the Daleks and Autons would occasionally appear, but the focus would be on the fall out from the Time War. I was a bit disappointed when that failed to happen in the following years.