OK, I think I have this straightened out. The situation was that only my first couple of PixelFed posts showed up in my Mastodon timeline, anything more recent did not. Somewhere along the way, I unfollowed and refollowed my Pixelfed account, to no effect. Today, I went into my Mastodon settings and saw that my Pixelfed follow was "Pending". I canceled it and followed my Pixelfed account again, and all is well.

I have to say, as something if a social media virgin, I am puzzled by #4. I have never been a Facebook, Instagram or Twitter user. Previous to getting into the Fediverse, the only platform I engaged with that could be considered social media was Reddit, and I left that behind because of the whole brewhaha over third-party clients.

Since finding my way here, I have become an enthusiastic user of Mastodon, Pixelfed and Lemmy. I could not have imagined that it would be easier to acclimate myself and i have not encountered any barriers to entry, or at least I have not recognized any.

Is my experience atypical?

Agreed. This is my position, exactly. Although I do consider myself to be an agnostic atheist, I am open to the idea that there may be a god or gods. I just don't think that it is likely, and so I conduct myself as if there are not. The main point is, l don't know, and I don't think it's possible to ever know for certain. That's why I qualify my atheism (or maybe nontheism is more accurate) with an "agnostic". If people were completely honest, I would wager we would find that most of the people in church every week are actually agnostic, but agnostic theists, rather than agnostic atheist