A fair question :). Let me summarize:

* KDE Frameworks 5 made its first stable release on July 7th, 2014. That's since been followed by Frameworks 5.1 one month later. It's monthly releases from here on out. This is production-ready code.

* KDE Plasma 5 made its first stable release on July 15th, 2015. This was followed by Plasma 5.0.1 one month later. Plasma 5 does monthly maintenance releases, while feature releases are on a three-month interval, i.e. Plasma 5.1 will be released in October. 5.0 is considered a stable release, but it's a dot-oh with some rough edges (nothing comparable to 4.0 at release, though), and the distros are also still doing their integration work right now. The release notes and an errata list provide some guidance there. Most distros will replace Plasma 4 as default with 5.1 or 5.2 later this year, when everything will have settled nicely.

* KDE Applications is doing a 4.14 feature release this month. This will be the last one built entirely on the KDE 4 libraries. Future KDE Applications releases will start shipping ports of apps to Frameworks 5, at the discretion of their individual maintainers/dev teams (some have had porting branches for a good while).

> Will Kubuntu ship Plasma5/KF5 next release (14.10) even if the applications are not yet ready?

I'm not 100% on top of the plans of the Kubuntu community, but I believe 14.10 is still going to use Plasma 4 by default - you might want to look into that more closely though, I'm not certain. I'm sure they'll offer Plasma 5 for interested users in some form as well though. They probably do already. KDE 4 apps still run in Plasma 5, of course, so that's no limitation (and KF5 apps also run in Plasma 4, for that matter).

Yes, on the promo front this does mean we don't get to do a big "BANG! It's KDE 5!" moment, but it also has some advantages for promo - e.g. driving home that KF5 isn't useful just for making apps that run in Plasma, and by implication that KDE Applications aren't useful just in Plasma.