Finding a position you want is only half the battle, there's typically a multitude of ways to put on that position, all of which have their respective advantages and disadvantages.
Regardless of whether the market is random or not, certain assets are intrinsically linked to each other such that we can create portfolios with them that move in non-random ways.
Yes and yes, it’s just about when and how likely it is to be one vs the other, which is able to be calculated.
One timeframe/tick interval isn't inherently better or worse to test or trade on, and viewing multiple timeframes is useful in many ways. But your trading style, holding period, and edge are dictated by the timeframe you're using.
When it comes to analyzing your strategies, one size definitely does not fit all. Here's a rundown of some popular analyzers in use.