Well, naturally, you should wait until you read the finished Codex before making any conclusions, but for now it would be a good idea to delay any major investment into Feral Orks. If worse comes to worst, Feral Orks have been a fringe ruleset for a long time, so I doubt that many players who allow you to use the list now would object after the Ork Codex is re-released.
And, with Apocalypse being a more loose ruleset, there should be no problem.