Could one say " ibland sjunger jag." Or would that sound grammatically incorrect to a swede?
I think moving the adverb around like that does affect the emphasis, modifying the meaning a little.
"Bland" does mean "among(st)". It's used much in the expression bland andra, meaning "among others". Ibland and bland are separate words with separate meanings.
What about "from time to time"? Does Swedish express that markedly differently?
The swedish equivalent would be "då och då", but i think ithe meaning is more or less the same.
We can play that game all day with many English phrases :)
once in a while, every now and then, every so often, from time to time, now and again, now and then, sometimes,...
Do you mean because of the infamous Swedish SJ sound ? You'll see it discussed many times in other threads because it only exists in Swedish and it's difficult for us. https://forvo.com/phrase/jag_sjunger_i_k%C3%B6r_%28substantiv%29./