Hi,
1) The ADV7181C can decode closed captioning on the incoming YPbPr data provided it is processed by the SDP core. VBI data cannot be decoded on YPbPr data processed through the CP core.
For more details, see Section 8.17 of the hardware manual available here: http://ez.analog.com/docs/DOC-1621
2) For NTSC, the standard for closed captioning is EIA-608. For YPbPr, captioning is present on the Y signal.
3) No, the ADV7181C can only process and output on input at a time
Regards