1. That's right. I would probably translate "raithneach" as "bracken" (which is a specific kind of fern, typical of the Irish countryside).
2. Yes, "tamall" is a noun meaning "a while, a period of time", but it can also be used adverbially to mean "for a while".
3. You'll find lots of variant plural forms in the dialects.
4. This is a feature of Munster Irish. I would use the indirect relative "a raibh".
5. Falla = balla, another dialect form.