There is very little discussion on Ubuntu phones because up to now there have been very few ubuntu phone users. We get a lot of posts asking if Ubuntu Touch can be installed on this phone or that phone and all we can do is provide a link to a wiki page. There are also few forum members porting Ubuntu Touch to other devices. So, not much discission on those areas. Besides a certain IRC channel would be the best place for those wanting help with porting.
There is nothing stopping you from starting a thread in this section fo the forum. What response you get will depend upon how many forum members have possession of a Ubuntu device.
As for caldav/carddav server syncing a question about that was asked on Discourse Ubuntu. I recommended the person to ask about it on the Ubuntu Engineering Q & A on Ubuntu On Air. And 2 days later the person did actually ask the question of a couple of Canonical Engineers. Well: that is the purpose of the Q & A. The response was: It would be nice to have and anyone is welcome to develop that functionality.
http://discourse.ubuntu.com/t/what-is-the-status-of-carddav-caldav-on-ubuntu-touch/2068
Every week on Ubuntu On Air there is a Ubuntu Community Q & A. For several weeks most questions have been about Ubuntu phones. Although the Canonical employees present are involved in the community side of things they are programmers and they have been running Ubuntu Touch on Nexus devices. They have also written some useful phone apps.
Every two weeks on Ubuntu On Air there is a Ubuntu Engineering Q & A. So, we have a couple of useful places to hang out at.
Regards.