IIR not fully causal?

Two papers that are freely downloadable and discuss some of what I
described:

I. Kaupppinen, K. Roth:
"Audio Signal Extrapolation - Theory and Applications"
DAFx-02,

I. Kauppinen et al:
"Interpolation of Long Gaps in Audio Signals using the Warped Burg's
Method"
DAFx-03.

Both are available from the DAFx homepage:
http://www.dafx.de

Regards,
Andor