@ph4wks: if you just want to quickly preview a link (either to a note or a note heading), you can hold ctrl and hover cursor over the link for a pop up preview.
Assuming your note already has headings within it, the heading link creation process can be completed by pressing the open square bracket twice then beginning to type the name of the note and/or using the up and down arrow until the correct note is highlighted. With the auto suggestion dialog still visible and correct note highlighted, add a hashtag and you will get suggestions for the headings within that note to be linked to.
Be aware that changing the actual heading name within the note (the one you were linking to) will cause any links to that heading to consequently just link to the note. That is, they won’t be updated as is the case with regular note links, and because the link will be trying to go to a non existent heading within a note that does exist, it just takes you to the note. In these cases, you may want to use a mass search and replace to fix the errant headings.
In terms of embedding (or transclusion), it works while in preview mode and can be accomplished by simply adding an exclamation point before the first open bracket of any link, including those to headings. I hope this helps. I know that when I learned this it opened a world of possibilities, so was happy to pass the good news along to you.