What should I use to write / design HTML pages?
Can I write/edit HTML with WRITE ?
If you mean coding html with Write or Writer, I suppose you could, but I would strongly advise against it.
If you mean editing and formatting “wysiwyg” using the old and discontinued Windows Write (or MacWrite), and save the result as html, this is not likely to succeed. Don’t!
LibreOffice Writer is also a fairly clunky tool for building web content, and the html files will carry lots of metadata pertaining to hardcopy, which in some cases will mess up the display, in particular when you use the html file within a “website builder” framework.
In the situation where you have existing Writer files and need a quick way to “webify” them, simply saving to html is ok.
What should I use to write / design HTML pages?
That depends on your skill level, preferences, and the purpose of the web pages. Except for the special case I mentioned above, LibreOffice apps are far from optimal.
See this web page (click link) to get a rough overview of possible tools and strategies.
OK, so what do you recommend?
I am used to DreamWeaver, had a LifeTime versions since 96, but Adobe stole that and forced me to buy the new version last spring. The new version is, by comparison, a real piece of Sh**. However, for simple stuff it does work. It is now locked up on a dying machine, so I need a reasonable web editor for a month.
I tried HTM-Kit, which is a total waste of time.
I rather edit right on the server with NANO than use HTML-Kit.
What do you recommend?
I can’t get LibreOffice to work on this W7 laptop, so Libre Office Writer is not an option.
For myself, i code static content by hand. Notepad++ mostly. That would be the same as your nano edit.
For dynamic content I’ll use some cms. Wordpress is not a bad choice.
I do not have sufficient experience with different web page authoring tools to advise on good software choice beyond the link above. Last time I used one was in a century long gone. In the late '90s, HoTMetaL used to build streamlined sites and had good tools for debugging and visualizing, where Front Page seemed to clutter up everything. This knowledge is now obsolete.
I do think that I have sufficient experience with LibreOffice Writer et.al. to state that that’s not it. Also, the Writer app is within the scope of this site, and web page authoring isn’t.
Most WYSIWYG-editors for plain HTML are now online - the “Cloud” has eaten its children 
As an old last century DreamWeaver-user I occasionally grab some old copy of Kompozer, Bluefish or Bluegriffon, but then there are decent online editors like HTMLPen for working with single static pages.
HTML-output from LibreOffice can be usable, if run through something like HTML Cleaner or amended in some text editor.
I use Bluefish all the time, although on a Linux box. It has many features that make it much easier to use than a plain text editor, and does not add a lot of bloat like some of the wysiwyg editors. I believe it also conforms to all the W3C standards (although of course you can intentionally violate them, if you wish).
Please note: “Some features of BlueGriffon® 3.1 are only available if you buy a license.”