2. The first line of the function should be t.Helper().

That isn't necessarily the case: sometimes you really do want to report line numbers from inside the helper-function rather than outside. (It largely depends on whether the function is implementing the body of the test, or just doing a bit of opaque setup.)

1. The first argument should always be t *testing.T.

I'm also not convinced of this one. The documentation for context indicates that context should almost always be the first argument. I interpret the "almost" to mean that the cases where you use a newly created context in the body of the function, rather than as a function param, are pretty rare. Not to mean there are cases where you pass a context as anything other than the first param. It is also a rare case that a test would need both the context and t *testing.T, so adding that contingency seems superfluous. The linter always expecting that context be the first argument seems preferable to me.

I find it pretty confusing to have lots of functions in tests that don't take a context.Context read as
func a (t *testing.T,...)
func b (t *testing.T,...)
And then have the outlier that uses a context (whether it is needed to run the test or be under test) read
func c(ctc context.Context, t *testing.T, ...)
I need to re-adjust my reading and instead of just kind of acknowledging the presence of testing.T, I actually need to think about it.
To me, having the "almost always" part interpreted as "with exceptions, one of them being functions in tests that take a testing.T argument" would be preferable.