UAE looked pretty good during Asian Cup, i don't know what happened to them during this qualification. They are for sure much better than Qatar, Bahrain, Jordan, Iraq.
UAE suffers from having shit players at the back. They have a few very good players upfront though (Mabkhout, Khalil, Abdulrahman brothers and sometimes Matar).
Japan has two tough matches vs Saudi and Aussie. Aussie will face Thailand in another match, much easier schedule. Saudi will play Japan at home. Japan play Aussie at home and Aussie has the best chance of advancing with Japan as the 2nd team, unless Saudi beat Japan at home!