wrt Android, adding an alt to the Coinomi wallet seems fairly straightforward according to Ahmed Bodiwala's commit of Ixcoin support:

https://github.com/Coinomi/coinomi-android/commit/0be43f98f88041adf91ef8f3adfc703caa7d181b

Of course, the proof of the pudding is in the eating, as they say.

Cheers

Graham