Who was the top of the social status in Ravloe in Silas Marner?

The answer to your question can be found in chapter III, where the narrator tells us who is the most powerful man in Raveloe, and gives us information about his family and how he is perceived in the community.

The greatest man in Raveloe was Squire Cass, who lived in the large red house with the handsome flight of stone steps in front and the high stables behind it, nearly opposite the church.

This description of the home is given through the viewpoint of the citizens, who are obviously impressed with those “stone steps and high stables.”

We are then told that he holds a strong standing in the community as one of the few landed people there

He was only one among several landed parishioners, but he alone was honoured with the title of Squire

From the landed people in the community, Cass was almost at the same level of deference as the Osgoods.  This clan, along with the Cass’s, are considered two of the oldest families in Raveloe.

…. Mr. Osgood's family was also understood to be of timeless origin—the Raveloe imagination having never ventured back to that fearful blank when there were no Osgoods….

Yet, out of the two families, Osgood “merely owned the farm he occupied.” Cass, on the other hand, has tenants. This places him at a higher standing since he has people whom are dependent on his land and property. These tenants, we are told, “complained … to him quite as if he had been a lord.” The implication of this statement is that these tenants treated Squire Cass with high respect (as people often do to those on whom they depend for whatever reason) and, as such, Cass has continued to be treated by others.

Squire Cass enjoyed his status and showed it off plenty of times with feasts for the community either at his own home or at The Rainbow Inn, which is the community’s public house. He felt entitled to the treatment he got, as he felt that he had a 

 hereditary duty of being noisily jovial and patronizing. 

Yet, Squire Cass is the quintessential example that money and status does not guarantee success in every area of life. His two children, Dunstan and Godfrey, are useless, to say the least. Dunstan, especially, is perhaps the most reprobate member of the community. He is the thief of Silas’s money, and has led his older brother to a downward spiral complete with an opium fiend wife, an illegitimate child, and financial ruin. 

Hence, that Squire Cass and his family are at the top of Raveloe society does not prescribe that they are also the most successful people there, the ones who have done best for themselves, or the ones who most deserve to be happy.