My kid hated it but ymmv.

It won't hurt, but I don't know that it makes a massive difference either. My son used it in his elementary school and I did not see it as something integral to his learning. The one-on-one time with his Special Ed team was much more helpful. That being said, he liked to work toward completing levels and he was engaged on it, so I chalk that up to a win of sorts because it did reinforce the things they were learning.

No they do it on their own during downtime. It is not tied to instruction

Is this in addition to reading instruction from an actual teacher? If so, it's probably ok. My son's private school for kids with dyslexia used Lexia for his homework (like he would get an assignment in Lexia to do at home) to reinforce what he was learning in school. It depends if your child is able to focus and work on it on her own and/or if a teacher can make sure she's on task and not messing around online. Lexia should be able to let the student know whether they got something correct or not, which is a plus.

DD is expected to work on Lexia during Learning Seminar. If this is going to help her I am all for it but how effective is Lexia for a dyslexic child? My neighbor’s DD works on assignments that target the goals from her IEP during this time instead of Lexia. Wondering if this is a better fit for DD and something to explore with the IEP team