but as ibus-mozc is suppose to be an japanese ime can direct input mode not be used to input kana and kanji? if so how does one do that?
This is about ibus-mozc on 16.04 LTS.
You have to activate ibus first, then set your favorite MOD Key for toggle ibus on/off by default, probably it is set to Super + Space but this might conflict other global hotkey/keyboard shortcuts, I recommend to change it, e.g. Control + Space or R_Alt whatever you don't usually use it.
When you type alphabet ibus off, when you type Japanese Hiragana ibus on.
p.s. Now I think fcitx-mozc has less problems than ibus-mozc. And ibus team will release a new project soon after 17.10 and 18.04 LTS.