Now that the merger has happened is there any roadmap for when releases will happen and what the changes will be?
I don't think there is a clear roadmap for what things will be included in what release, since code is being added by volunteers. Security updates will happen whenever needed (For example when WPA Krack was discovered) and bugs are fixed every now and then in a new release (17.01.1 through 17.01.4).
I agree with you that it would be nice to know whether there are any timeframes in mind for the next 17.01.x release, and when there is going to be a new build based on the current master branch. So many new and interesting things have been added since January the 1st, 2017
There was a LEDE roadmap in early 2017, so that there would have been a major release 17.06. But that got postponed after the merger talks were ongoing. The practical merger got quite much delayed, so there was no second release in 2017.
There was discussion in several threads on lede-dev mailing list on October about the next possible release, and it may be a mix of 4.9 and 4.14 kernels.
17.01 stable is pretty much old now and a lot of devices are missing.
Especially TP-Link ones of which older revisions are not available.