Citra and Apollo are awesome hops together. I've got a hop bill for a session IPA that I scaled up to a standard American IPA using Citra, Apollo, and Eureka that was excellent. Both of those hops go a long way though, so be careful not to over do it. Apollo tends to have a kind of sweet orange & dank character that blends well with hops that can brighten it up a little bit in my experience. Citra is tropical fruit & mango...but can turn kind of deisel-y and gym-socky in my experience if you over do it, or get a bad crop. Maybe shoot for a 2:1 Apollo:Citra late/dry hop in an IPA or Pale Ale?
The Session IPA hop bill was .5oz warrior FWH (you could use your apollo for this, too), .5oz citra @30, then 1oz each citra/apollo/eureka at flameout for a 20 minute whirlpool. Then 1oz each citra/apollo/eureka in the dry hop. Turned out with at ton of citrus and fruit. Without the eureka I'd probably just sub it out with another oz of Apollo.
Can't speak much to the strengths of EKG and Northern Brewer...other than EKG is typically used in english styles and from what I understand Northern Brewer provides an almost minty-herbal character that goes well in dark beers like browns, porters, and stouts. I've brewed with them before but don't usually buy them for recipe planning.
Agreed with Build, EKG/NB could be good for your stout coming up. I personally usually leave late hops out of my stouts unless I'm doing an American style stout, then I'll generally go for columbus, centennial, or the like.
In any case, update with what you do with them! So many threads like this die out without ever hearing back on how the recipes turned out.
