taw:

Weregild was not a penalty, and had nothing to do with guilt. It was debt towards family to compensate for their economic loss with no consideration of "guilt" whatsoever. Wikipedia doesn't say so, but it was debt of extended family to extended family.

As you say, these people were illiterate, and they didn't leave much record of their feelings and abstract opinions in these cases. But the fact is that if you killed someone, you'd be obliged to submit to legal sanctions, and if you failed to do so, you were in big trouble. This is not a situation that follows after acts that are considered "totally casual," and whatever were the old Germanic words used to describe people in this situation, "guilty" seems to me like an accurate modern English translation. The fact that these sanctions were administered at clan level changes nothing.

Even as late as 19th century there was no legal personhood for most women,

That is true when it comes to property rights, contract law, etc. for married women. But it doesn't mean that killing women was legal, married or not. You are making invalid analogies.