Ciao Caroline and welcome to our forum!
Congrats on your upcoming honeymoon trip, 5 nights in Montalcino are perfect for a wine lover!
The wineries on that post are definitely just a selection from a variety, from small family owned to larger estates, with some that have a lot of years of wine making and others that are pushing the limits on innovation within the set standards for local wines. So take them just as suggestions on where to get started.
Keep in mind there are over 200 wineries around Montalcino, so everyone will come up with a different list
From your list,
Fattoria dei Barbi is the only one that comes to mind right away because it also has a museum dedicated to wine-making in the region:
https://www.fattoriadeibarbi.it/en/hospitality/brunello-museum/
Castiglion del Bosco seems to be an estate bought by the Ferragamo in the early 2000s that a century before belonged to the Biondi-Santi family, which are the original creators of the Brunello. This is one (the
Biondi-Santi estate) I would recommend you add to your list, maybe as one of the first you visit so that you can then compare others to it. See what you think of the differences

.
In any case, Castiglion seems to be pretty big and a luxury resort now, it really depends on what kind of experience are you looking for.
Small, boutique and family-run? Or something larger, more commercial? Keep in mind the vast majority of the brands and estates you might encounter are likely ones that either don't bother with commercializing or marketing overseas because of smaller production (so they concentrate on specific markets) or are so small they can't compete on the marketing budgets. It doesn't mean they are lesser in quality. Take the Bartoli Giusti brand, they are pretty well known but their website is very very "homey" and old-style, the estate is run by brother/sister. But they have been making wines for DECADES! They don't even seem to have an English version of the website

Ok, don't choose them, they don't even try a little bit!
I am sure there are particular aspects of the wineries on your list that called to you, so make note of what appeals to you and then make the hard decision of just choosing 4!
