What might the minimum data requirements be for developing a successful stratey?

I know this is more of a question for algotrading but I don't have the karma or whatever to post there yet. Plus they're pretty intense over there!

I'm building out a platform for backtesting, and building bots and trading tools in general.

My question for experienced traders is this - what might the minimum data requirements be for developing a successful strategy be? I'm thinking something like this to start:

\- Daily bar data going back a few years

\- Corporate actions (dividends and splits)

\- Select fundamentals, the basic like eps, shares outstanding, pe, market cap, etc.

The general idea of the platform is that strategies are scriptable in es6 with access to point in time data depending on the replay time. Like quantconnect but aimed at higher timeframes and a fraction of the complexity of getting started with.

Any help/feedback would be much appreciated!