TeqToo: When you create a new document on your old computer, does it automatically have paragraph and/or character styles in the panel? If that is the case, then you have “default styles.”

As others pointed out, your documents will all come across with their styles just fine. But those default styles may not. But you can capture those by:
1. Creating a new document and saving it with any name. (That document will have all the default styles in it.)
2. Move that document to the new computer.
3. Launch InDesign on the new computer, and while no documents are open in InDesign, choose Load All Text Styles from the paragraph styles panel menu.
4. It will ask you for a document to load them from; choose the new document you just created.

Now all the default styles will appear in InDesign. Because no documents were created, they become the default styles in the new document, too.

Remember: you should (almost) never apply a character style to a whole paragraph of text (or all the text in a cell). Use paragraph styles for that.

Because the text expanded after you opened the IDML file, I’d say that the expanded version is “correct” and the squished into the frame version is the anomaly. Don’t know why that would have happened, but you would likely need to use tracking or H&J settings to tighten it up, such as:
https://creativepro.com/adjust-word-spacing-in-paragraph-styles.php

As for getting ITC Stone, that is a commercial font, so you’d need to buy it at fonts.com or Adobe or some other distributor.

Is anything selected on the page? If something is selected (or text cursor is in text), then zooming centers that.

I believe you have uncovered a big difference between the Adobe programs. InDesign does not support the Stylistic Alternates feature, while Photoshop and Illustrator do. See the big table near the end of this post: https://ilovetypography.com/OpenType/opentype-features.html

However, you can use the Find/Change dialog box to do this. Don’t forget to use the Load Selected Glyph in Find (and Load Selected Glyph in Change) features in the context menu!
https://creativepro.com/finding-and-changing-glyphs.php

Carole, no there is nothing wrong with your solution! Some people like having a single text frame to hold everything, but two frames is okay.

I have heard that several aspects of InDesign’s XML import (and output) are half-baked and really must be scripted and massaged. I know in some cases people build their own custom XML import using plug-ins and scripts.

There are InDesign XML experts out there, such as Andrej:
https://creativepro.com/formatting-text-xml-indesign.php

and Claudio:
https://www.slideshare.net/mclaud/ignite-id-pepcon-2014

and the folks at Premedia:
https://www.premediasystems.com/Scripts.htm