For Saudi Arabia not only do they have a pretty good performance, but also they have the advantage of playing at home since they are the host, so that increases their chances of winning the group and qualifying directly for the World Cup. As for the other team that has the opportunity to win the group is Qatar, in terms of their performance it is also as good as Saudi Arabia and again they have the advantage of being the host in this round 4. So I think Saudi Arabia and Qatar will qualify for the world cup. But this is still just a prediction, Indonesia or Iraq could come out as the group winners (only if Saudi Arabia and Qatar can play more fairly).
Yes.. I almost forgot that. The fourth round matches will be hosted by both Qatar and Saudi Arabia. But I don't expect a lot from Qatar. They were pathetic during the third round, and lost matches against teams like United Arab Emirates (and that too by a margin of 0-5). Also, Qatar is still dependent on "imported" players, such as Lucas Mendes (Brazil), Almoez Ali (Sudan) and Mohammed Muntari (Ghana). Anyway, the fact that they are one of the hosts may give them some advantage.
Saudi Arab is one of the best teams in this list with the UAE, Qatar and Iraq can make things interesting because these done good job in early rounds and have good chance of staying in touch for promotion I am not expecting Indonesia will be make any mark because all matches are going to be played away for them.
Qatar is having few players those are imported but UAE and Iraq are teams which can make life difficult for any team in these qualifiers because they are having few skilled and talented players conditions will be suitable for host teams while visitors needs to be had some adjustment. Saudi Arab is having good development in soccer which is giving them good advantage still it's long way for few teams to have consistency and better results which make them good for long run because mostly these teams are unpredictable and inconsistent.