Please take all rumors with a grain of salt. In this rumor, StraightSilver is referring to Stickmonkey's batch of rumors posted here.....
Everything SM says matches up to rumours I have, except the Chaos Dex could be May or June, with 6th Edition around about July.
I can't go into detail about special characters but there will be a couple coming that I know of around the same time as 6th Edition.
40k will get a fair bit of stuff this year, but expect it to be more of a trickle than a downpour.
I have heard there will be more releases than usual models wise, but they will be small releases to keep interest up for the whole of the 25th anniversary year.
I don't know if that means small waves every month for 12 months, or a blister or two each month but there should apparently be more than enough to keep all 40K players happy.
And Empire is definitely coming soon, April would be my guess too.