First of all, I am glad you took the time to post your questions again. I saw them the first time, but because I had a lot of school work to do I did not have the time to write an answer to your questions.

It is true that at least some Norwegian laws from around the 12th century mentions thralls. Gulatingsloven has a section of its own for them, and most likely the other regional laws also mention them, although I have not read them so I cannot guarantee it. These laws where valid until Magnus Lagabøte reformed them into one national law around 1270. The full book is quite large, and I do not have the time to read it, nor do I really know where to look for any sections about thralls or previous thralls. I would say it is unlikely that it contains anything regarding thralls as the amount of thralls in the country had declined after the 11th century. For mentions of previous thralls I would say it could be possible. The old law regarding thralls enforced connections between a freed thrall’s family and his previous master’s family for 2 generations, and it could be possible that Magnus Lagabøte sought to continue with this practice.

I would say it is unlikely that thralldom was widely spread out by the 13th century as the church had attempted to lower the practice by buying thralls and giving them their freedom and by encouraging others to free their slaves after Norway became Christian in the 11th century. After the Viking raids ended in mid-11th century it became harder to get new slaves and the amount of thralls in Norway would therefore decrease. As for how it was to be a thrall I will link you this answer I wrote a month ago. It touches on the amount of thralls in Norway, but not in the time frame you are asking about.

As for the Norwegian civil war era I am afraid I cannot say how an average person would be affected. Some historians have argued that the civil war probably started or at least lasted so long because there where many warriors who had previously raided who could no longer do that. In addition, the local resources in Norway was used and therefore the warriors joined various pretenders in an attempt to gain power and riches. As these bands of warriors roamed the countryside during the civil war it would be natural to assume that travelling was more dangerous than before the civil war and that these bands would forcibly take resources, sometimes to get supplies, sometimes to get wealth.

The civil war started in 1130 upon the death of Sigurd Jorsalfare. It likely started quite intense with various bands and claimants, but then settled down as Magnus Erlingsson got crowned king by the church in 1163. After that it was relatively peaceful for 14 years until Sverre arrived and started a guerilla war that lasted for seven years. Sverre won, but in doing so had made a lot of enemies in the church and a protracted conflict with the supporters of the church (called baglere) lasted until Sverre died in 1202. After that a relatively peaceful period began again, although there was still revolts, the last of which ending in 1240.

The people not owning their own land where called leilendinger. They rented areas of land from richer farmers or the church, and in return they gave away parts of their crops. The owner of these lands usually lived quite far away from the actual land and he was therefore freer than peasants through the rest of Europe. In the 12th and 13th century the contracts also lasted for 1 to 3 years and the leilending therefore had the possibility to move if he wanted to. Therefore the feudal relationship was basicly nonexistent .