All really good questions! The easiest answer for damage is focus first on your general damage (spells vs physical) and go from there. Remember that spell crit and regular crit are different, and damage over time cant crit. You typically want +stats in addition to your damage types, so lich usually benefits from +int, then probably +spell damage, and +poison damage.
Make sure to pay close attention to the skill tags, hover over your skills and see what they are. Lich in particular is cool but a little difficult to master, she excels in low life, ward based builds, and necrotic is a little easier to pump out damage usually.
Shaman is situationally fun once you figure it out! Flat totem damage, go thorn totem, get 5 points in beastmaster, use the spriggan form. Theres a way to get like 10 thorn and 2 storm totems :)
And get critical strike avoidance or minus bonus crit damage! Get one of those to 100%
Weirdly you can get more details on your profile at lastepochtools/profile/[username]
This may show you some more details, but yeah, the calculators are pretty lacking