Haha, well at least your ramblings aren't unnecessary.
No ramblings are unnecessary. If nothing else, they build a picture and make you human
My apostasy baffles my stepmother (she thinks exterior reasons like my depression might have been the cause of it)
I think it's more likely the polar opposite: I'm convinced that Islam is the primary cause of many, many cases of depression in the Muslim population.
and I don't think I explained my stance as an agnostic theist well anyways.
can't stress enough, take things slowly. I know it's not necessarily what you want. You're young, you're also in a generation that is used to getting things quick. But these people are your family and you need them by your side. It's an investment that will pay off - I've seen firsthand the results of parents disowning a child. The pain never goes away.
From my second conversation with her, I found that she expects to "be Muslim" around the family and that she has no idea how we would handle my relationships/marriages, future eids, or my funeral...
Being Muslim around the family, as you've already touched upon, is probably for the best. Could be a double edged sword for you, too: you'll keep your parents (including your step mom) on your side, and it may give you a more solid foundation of respect with your siblings, come the inevitable conversations about faith and apostasy, as they get old enough to start asking questions.
Perhaps plan the steps you'll take. Of course for this Eid and perhaps next, you'll do nothing different. Dress up, keep covering, go to the family events, pray when people expect you to (but
don't lead prayer if pushed, make an excuse, say you need to take wudu again, anything to get out of it). Then next Ramadhan comes and you've already paved the way for not fasting and not praying tarawih and not going to (every) family iftar. Take your mom and step mom (on separate occasions) clothes shopping, looking for long, modest dresses etc, that they'll find modest and not offensive.
Be explicit about looking for clothing that you'll wear instead of the abaya. Go out with them again a few days later, covering and wearing hijab, but wearing the dress they helped you choose but without your abaya over the top.
It's all about being clever, just how the apologists and sheikhs are when they're explaining things. Use the same tactics to keep your parents on your side, whilst showing them (more than telling them) you're serious.[/quote]
Well, anyways, it is good to know I'm still family even though I will be treated differently.
Absolutely. And may your experience be a reassurance for, and provide confidence to, others who find themselves in a similar situation to yours.