I absolutely love the alien characterization in Mass Effect it's my favourite thing about the series. Aliens don't feel human so much as they feel alive - more so than human characters in most other video games. When you observe other species on earth be it cats and dogs or gorillas, etc you can see character traits that you recognise in our species whether those be derived from base instincts or higher level communication in social species, e.g. selfishness, pettiness, paternal or friendship bonds, bravado, shame, empathy, pride.... those aren't merely recognisable human characteristics, they're universal.
The alien personalities of Mass Effect are universal character archetypes which we see in all of earths cultures and I would be shocked if they didn't permeate/apply to life on other planets. Religion might be a ridiculous human concept sure but it is so pervasive I wouldn't be surprised if alien cultures had their own notions about spirituality and life after death.
On artificially intelligent species I find ME2 Legion and Her much more plausible than EDI/synthetic Jesus as I don't believe synthetics would share our goals or value individuality or emotions (emulating organics basically); they would have their own goals/motivations which we probably wouldn't be able to relate to or even comprehend which might be the case with any civilization with an average intelligence much greater than our own. However I agree to an extent with Dawkins/that astrophysist who's name I forget who theorise that organic life doesn't get much beyond radio transition and nuclear energy/grey goo before it wipes itself out so the majority of life we meet out there might not be much more advanced than we are given that the more advanced one's might have already wiped themselves out, especially given the drake equation.