Have you bought MK:XL, the XL pack or Kombat Pack 2?

Yes

I hear it's a problem with those who bought the XL pack (KP1+KP2), I guess you'll have to wait until they resolve this.

I bought KP2 and got it. It has costumes for Takeda, Erron Black and D'vorah.

I know it downloaded. I'll double check those fighters to see if they have extra costumes. I don't use them very much at all so that is probably why I haven't looked.

There was an issue with those who bought the XL Pack on PS4 where the Apocalypse Pack wasn't included, but it was fixed yesterday AFAIK. If you still don't have them, go open the Playstation Store in MKX and "repurchase" the XL Pack. It should be listed as $0.00. Once you do it'll bring up a list of DLC included and you should find the Apocalypse Pack there, just download it individually.

Never mind I did get them. Didn't know what skins they were. Silly me.

Will the apocalypse pack and cosplay pack be available for purchase seperately?

I would like this too, it's annoying that it says available now on the home screen and then in the store, it's nowhere to be found.