If you use a handshaking scheme, then there is no need to know the exact port timing, since the handshaking signals reacts exact in the same way, as the data signals
I disagree, but only if external memory (code or data) is employed.
If two controllers "talk" via P0 there is no way to gurantee that processor b does not read the bus while processor a is fetching from memory. For that reason latches will be required.

Of course, if internal memory only is used any communication can be done on P0 with proper handshaking. Prasad, have a look at the Philips P89C66x offerings, lots of Flash and RAM inside.

Erik