You’re not getting any help because your post is confusing. It starts by mentioning parallel connections, which are speaker level, and it ends mentioning the LFE channel, which is line-level. Perhaps you could try again?
My receiver has a fixed low pass filter at 100hz. I would like to by pass this and use my subs variable x-over. This is because I have tower speakers that go down to 42hz, I would like to set my sub at 60-70 hz rather than the fixed 100. If I use LFE channel this can not be accomplished. I would obviously have to set subwoofer to "no" on my receiver if I ran a parallel. Is this a practical idea or does it have any implications??