Though Luqman was not a Prophet and I suppose there is no indication suggesting that he was a follower of any Prophet, he was granted hikmah (wisdom) by which he recognised and confirmed to the oneness of God and advised his son on various others virtues as well.

Based on this, could you kindly explain the following:

1. From the levels of guidance mentioned by Ibn al-Qayyim ,which level of guidance fits Luqmaan?

2.In the period of fatara , when no warner had come, is belief in oneness of God and good deeds sufficient.

We cannot discount that he was a follower of a Prophet unless if we have the evidence. That is an issue for research from history books like al-Bidaayah wa an-Nihaayah by Ibn Katheer. There are indications that Luqman was a black man.

1. Since he was not a Prophet he would have been given hidaayat at-Tawfeeq and the other types of guidance which are not applicable to prophets.
2. If no warner came and a person was on tawheed it is hoped that they will attain salvation.