Is it scriptural for just one elder or pastor to be the overseer of a local congregation?

I think we have to be careful and realize that churches find themselves in different circumstances, so not every general answer applies to a church in some extreme situation or difficulty.

There was a great church order in the latter part of the 16th century drawn up by the Hungarian Reformed churches. That church order covered all the normal things concerning how a church should operate and function. Then the last article said, “And for the brothers living under the Turk, they should do the best they can.” So there are extreme circumstances where we have to do the best we can.

Generally speaking, the pattern (as we see in Acts 14) is that wherever Paul went he established churches with elders. So, ideally, there is a plurality of leadership in the local church, because we all have our limits. We all have questions in lightning rounds that we can’t answer, and therefore we need help from other people who come alongside us. So I think the general pattern is to have a multiplicity of leadership in the local church.