When you’ve got more than a handful of horns, it is more akin to a flock of pigeons gathering ‘round your feet.
Hey, when the Internet gets knocked out by (insert some world changing event here), you'll be glad that you have such easy access to a trainable messenger. I'm kidding... I think. And if it's an economic ending event, be glad that you have those horns to busk for... whatever currency we may be using. Still kidding... I think.
Regarding saxophones, they're tangible assets and even the lesser models of known brands appreciate in value over time. I mean, not if you buy new. A Selmer Supreme, for instance, is going to take years to command a price greater than what they're going for right now. If you find good deals in the used market, yeah you can flip a nice profit. Not saying that I'm even looking to sell any of my collection, but it's something I absolutely do keep in mind.
I do have 2 similar Yamaha altos. A Vito 21 alto, which is a rather unique prototype instrument, and my primary just because it looks cool, and a standard 23 that can use about $70 worth of maintenance to get it up to snuff. The 23 was given to me, and I can easily fix a few things in order to flip it. I already have spare altos. Now, what I don't have is another similar model to my primary that will play identically, because the 21 and 23 are exactly the same where it counts. Not only is it convenient, but it justifies my keeping both.
So, I'm kinda a fan of your collection already. That 25 legitimately appeals to me, because of its somewhat unique nature and vintage. You know your situation better than I do, and I've most certainly sold a few horns and have given away others. In regards to Yamahas, they're all going to basically play the same. If you're looking to get rid of anything, get rid of the less unique varients, as outliers can be hard to come by. From a playability perspective, rest assured that you can easily find another Yamaha that plays as well as what you previously got rid of. They don't change much, and their QC is pretty incredible.
Frankly, doing what you're doing, I'd only sell one to get funds in order to buy another pitch. There's a few reasons for that. Firstly, let's address the elephant in the room. There are very few gigs that justify bringing the S,A,T,B lineup. Still, they happen, and people will see what you do on all 4 pitches. Sometimes, you get the soprano and bari gigs just because someone discovered that you have them. Sometimes, you get album session gigs, because you have all 4 horns. There's more than one way to make money out of playing the saxophone, and all avenues are valid as long as the check clears. Besides, going to the other pitches opens up ideas on your preferred primary. So, the more horns, the merrier.