Is it possible to search for a certain string inside the HTMLViewGo or even change the font color of a certain string (same as FormatTextAreaText)?
yes, you could wrap the text in a span and set a style for it specifically.
i.e.
some text <span style="color:#ff0000">Your text</span> other text
you can specify color in hex values, named colors or RGB values with rgb(r,g,b)