[yummyfajitas]

Stat arb is not what is commonly known as technical analysis. They are distinct.

No. Technical analysis is forecasting prices based on past data. Stat arb is a particular form of technical analysis, based mainly on looking for mean reversion in sets of securities.

Strictly speaking, statarb \subset technical analysis.

[confluence]

> forecasting prices based on past data

By your definition everything is technical analysis.

Which makes your definition useless.

[yummyfajitas]

Hardly - fundamental analysis exists.

Any strategy lies somewhere on the continuum of strategies ranging from purely technical (looking at past prices only) to purely fundamental (looking at fundamental data only).