Eventually, all ninjas will be able to be recruited with F2P means. How difficult it will be to obtain particular ninja will, of course, differ in each case.
Premium ninja like Tendo Pain and Playboy Sasuke ARE available for the F2P player. I know that China has a permanent event that acts as some type of alternate Ninja Exam. You can obtain stuff that I assume you use to upgrade (it's some weird scroll stuff we don't have), but every 5th battle, it is possible to battle and receive a couple of Tendo fragments. SUPER SLOW, but still possible
Playboy Sasuke, likewise, appears in Chase Missions in China from time to time.
As far as daily log-ins, I know that China is currently obtaining Choza fragments, which is interesting, and that they got GNW Sakura some time ago.
If we're talking about the english version, I don't think we'll be getting characters like rares or super rares for f2p players anytime soon, but as Dym said above, you'll probably pull whoever you were looking for through seal scrolls.
This post was last edited by DraconusNex at 2016-10-19 14:30