The OP really should invest in a HD621 to accompany his prospective 861v4 and thus avoid the unnecessary D-to-A, A-to-D cycles which occur with an analog connection between his Oppo and the new preprocessor.
Other than that, as my signature would attest, I'm also firmly a fan of his proposed gear choices.

2ch: Jay's Audio CDT2 Mk3, PS DirectStream Dac, Oracle Delphi VI/SME V/Benz LP-S, Coincident Statement Linestage, Foundation Research V5 Phono, JL Audio CR-1 xover
M-ch: OppoMod 203, Anthem AVM60, 2x 557
2x or 5x ATC SCM20ASL mk2, 4x SCM12i, 4x Seaton Submersive HP, AM2.0 sub EQ
Video: JVC X990, Isco 3L A-lens/sled, 105" motorized 2.37:1 AT screen