I have the LXs, run them with no sub. Love them. They were the lowest price option for a "no compromise on the measurements I am looking for" 2 channel system, and I am happy to recommend them. As are many on ASR, Ascend and Philharmonic are popular here for very good reason.
Three would make a good HT set up with a sub for under 100dB levels (guessing on that level btw). If I was not told that our current HT mains were not only never being sold, they are never being moved, I might be doing that right now. No, I would be doing that right now and just pulling them out for music.
I would go Arendal at that price + sub for home theater without a second thought. I would likely skip a matching center, I don't care for the treble rise in the center Arendal. I might go with Ascend's center with a RAAL tweeter, given long wall set up in a room. I would look for something with wide dispersion, and ideally a pretty close match in frequency response to the Arendals in the vocal region.
If I were going with Ascend for mains and center, long wall set up, I would definitely to with one of their options with the RAAL tweeter. Given a sub, no need for the extra extension of the LX, that would be my thinking. And honestly, they look a lot nicer than the Arendals to my eye, which is not a deal breaker, but it is a nice bonus.
You really can't go wrong here, the options are all good.