Actually you may want to be careful here as all the games may be connected the series hasn't just gotten far enough to elaborate, XBC2 has elements that reference X indicating a possible connection. Takahashi tends to have a large overarching connection with his work and X maybe the part of the whole arch that fills in the gaps of the numbered games in future.

As for the topic I think it's pretty obvious XBC3 would be in development regardless of rumours as Monolith have four teams (two in Tokyo, Kyoto and Nakameguro), Team 1 did XBC Remake and helping out with BOWT sequel, Kyoto helped with ACNH, Team 3 and 4 which were newly opened back in 2018 with one being relocated are on unknown projects.

Team 1 aka Production Team 1 were working on a new separate project at the same time on XBC Remake we know this from Takahashi himself as he said so in an interview regarding the former's development, this means the new IP is likely handled by one of the two new studios they created.

Between Khan and those backing him up, plus it not exactly being a far fetched proposition to begin with, I'm leaning towards this rumor being true. Being set in the far future should be interesting as it gives Monolith the opportunity to refresh the setting instead of being too closely tied to 1 and 2, so I like the sound of that. It's also nice to hear we can probably expect it in the first half of next year, instead of being a long ways off.

If Nintendo have another September Direct this year maybe we'll see it there. 

That is possible, I was just trying to explain things simply to someone unfamiliar with the series and confused about the different games.

Disagree, Counterattack, Walking With You and One Last You are at least on par with XC1 music and way better than X ost, especially One Last You, the lyrics make it a way better song than Beyond The Sky:

Very end of eternity
The final day has come to an end, it's gone for good
I would then slowly close my eyes
And be cuddled by the shining memory piece
I will trace back all the memories with you
That's the only wish I have

The last day with you was truly magical
The frozen time began to flow
At last the longest night has gone and brought in light
I felt myself melt in the morning light

The final grain of sand has dropped
I will slowly so quietly fall into sleep
I see you gently fade away
Your silhouette has gone to the other side of the mist
And all the memories with no sound so quiet
Just like in slow motion it moves so slowly

And so the last day with you was truly magical
The frozen time began to flow
At last the longest night has gone and brought in light
I felt myself melt in the morning light

You have gifted many things to me
(But I) wonder if I could've done the same for you
If you would let me, I will give back a handful
If it would put a little smile on your face

Can I ask you, God? Despite all of this...
Could the sandglass somehow take back the time?
One last time is all I ask from you
Can you please spare me some time with the one man I loved?
I wouldn't care how and where (you could) it should be
But I need one last time I want to tell you, how I feel inside for you
I want you to know...

https://youtu.be/uq0YbOn_eSY

The closure of Beyond The Sky gives me goosebumps, man, so much that I would like to play the song in my wedding, if I ever get married. The girl from One Last You doesn't cut it for me. 

Xenoblade 2 has a better OST. Xenoblade 1 OST is stunning. X has a lot of good stuff.

Xenoblade 1/Chronicles same game

Xenoblade 2 is a sequel and all I will say but it's a sequel for a reason. But you can still play it without playing 1.

Torna is a prequel to Xenoblade 2 but a game you play after finishing 2.  Sounds confusing now but it makes sense in the context of the games.

X is stuck on Wii U and likely will never come to Switch. Monolith had a choice of porting X or remaking Xenoblade Chronicles. They chose the remake.

X does not seem directly connected as of now but it's debated by fans with theories from clues in the game it might be connected. The story of the game itself is self contained entirely.

I gotta take Beyond the Sky over One Last You personally.

They're both beautiful, but the end of Xenoblade 1 got me more emotional and felt more like the end of a long adventure with people I'd come to know and like deeply, as such saying goodbye to them was more poignant and bittersweet.

Beyond the Sky is just... Oof. It's divine stuff!

I hope it's more like the first one. I loved that game.