The standard at my MO high school to be considered frum was Shabbos, Kashrus and Taharat hamishpacha. Now obviously, Shabbos and Kashrus have wide variances in observance, but basically, if your intent was to observe, you were considered in.
Conservative is basically its own halachic movement that uses halacha as a guide, and claims to adhere to it, but they accept every lenience and make their own if they feel like it (driving to shul on Shabbos ok).
The chatam soffers reform is NOT the reform of today. The reform of today believes that halacha is valuable, and you should do as much of it as you can, but its an individual choice. This is much different than the views of the past that many of the laws were ridiculous, etc… Todays reform recognizes the value of all halacha, they just “pasken” that its not mandatory (but it is still aspirational) and they also change things to be egalitarian.