I think that with the likely exception of "finger/strap is in front of the lens", none of these are Things To Avoid.
They are things to be aware of when making a composition, which is very different. Depending on what you are trying to accomplish, they very well may be exactly what you want. Having an interesting part of the image cut out is a prime example: that may make the point of the image less immediately obvious, but that's often a good thing.
There are two different questions at work here.
One is: what technical mistakes should I avoid? For example: finger in front of the lens, focus not where you want it, exposure doesn't reflect your intentions. Those are generally bad because they're not what you meant to do.
The second is how do I manage tension and stability within my image? Balance is important in composition; too much balance is static and boring. A completely obscure subject doesn't interest the viewer enough to look at the image; a too-obvious one doesn't keep the viewer engaged. "Distractions" can detract from the intended subject, but they can also make the photograph more complex than a simple clichéd shot everyone has seen before.
I'm sure you know the expression "rules are meant to be broken". It's good to know the general expectations for "proper" composition, but it's also good to know when to follow a different path. I once saw a great series of pictures containing the photographer's shadow in the bottom of the frame — generally, a tourist-snapshot mistake, but if that's what you want to work with, go for it.