priceSet does not create bars, but it can fill or overwrite price candles.

priceQuote can indeed trigger a call to bar(), at least I would expect that since it is equivalent to the arrival of a tick. But as I said, it has been tested so far for HFT simulation only, so it's not guaranteed that it works for receiving prices during live trading.

Updating a .t6 price history file can have only an effect on the backtest when you do that at test start before selecting the asset.