Yes to your first question. If you start with “She reported,â€ then everything that follows is attributed to her.
The second question is a bit different. As you know, we can write/rewrite every sentence multiple times, depending on what you want to emphasize. So here are options.
1.  She also tried a few electronic magnifiers during a vendor demonstration and found them very helpful. She wears tri-focal glasses, but they are not helpful for reading. (we have to assume that she said, “They are not helpfulâ€ because who else would know besides her?).
2. She also tried a few electronic magnifiers during a vendor demonstration and found them very helpful. She wears tri-focal glasses, but she said that they are not helpful for reading. (Now, it’s very clear that this is her opinion).
3. She also tried a few electronic magnifiers during a vendor demonstration and found them very helpful. As for her tri-focal glasses, she does not find them helpful for reading. (This is crystal clear.)