Sound like some good alternatives; picking what's "best" gets down to a lot of subjective judgments. I think in your shoes I'd get the Lightheart SoLong despite the extra weight, just given your height and when you're going (i.e., you might spend a lot of nights in that tent). I think your pad might be overkill even with the UL version, but if it's something you otherwise want or already own, then so be it.

Key suggestions I would make are to focus early on getting the right footwear --- something you can wear for all-day every day, so whatever you think will work for you I suggest you get a pair now and start doing some local long walks to verify. Getting the right footwear can be difficult, but important.

The other thing is to get your gear together (all of it, not just the big three), perhaps rent a pack if you're not yet sure of the overall volume/weight you'll end up with, and do a multi-day solo trip. A shake-down trip, 50 miles or so if you can find the time. Take notes along the way of both gear and hiking 'style' issues. Perhaps take a thermometer along to calibrate temps that way.

Best of luck in your preparations!