Hello!
Well, although you can't get the latest and most expensive phone out there, you really don't need to with the lineup you've got there! All of those phones would make good choices, in my opinion.
The Nexus 6P is a great buy. It was one of the better phones when it came out, and I highly recommend it; even today. There are users on the Nexus 6P forum threads here on Android Central who are still using their phones since its initial release and loving it! The only thing I would caution you about is that Google is going to stop putting out updates for the 6P (it's either already happened or will happen soon). However, that doesn't mean that it's not a quality device: the phone will still work fine and will serve you well! To illustrate, Google has stopped pushing out updates for the Nexus 5 and my coworker was using it up until about three months ago with no problems.
The LG series devices you are looking at are stellar. Either of those phones would be great! Large displays, good quality screens and colour (from what I've heard), and LG's customer service is pretty good. I'd contacted them about my G3 and they got back to me very promptly. LG is a good software experience in my opinion, although the LG skin is not for everyone. However, you can just slap on another launcher or theme of your choice and voilà! Problem solved.
The Axon 7 is a very good choice. If you're looking to not spend a ton of money and to also have a good phone experience, this is the device for you. I've heard really good things about it, and had briefly considered buying it unlocked before I bought my Honor 8.
My advice to you is to watch unboxing and review videos on YouTube (Android Central is obviously a great source, but Android Authority is another channel I jump to for quality reviews). Also, if you can, try to grab a hold of these phones in the store to see how they feel in the hand. You may find that one phone "works" better in the hand than others - sometimes, they can be similar in size but one is a better fit for you, literally! Seeing them up close also helps you figure out if you'd be okay with looking at that phone every day for two years or for however long your contract will last.
Also, if you buy your new phone in person, do not let your sales rep influence your decision. Sure, let them answer your questions and give you some input; but some sales reps will use their own personal biases to try and convince you to get the device they think you want instead of the one you actually want.
Good luck, and please reach out to us if you have more questions or need anything else! And let us know what you decide!
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