Your question seems to be a little bit ambiguous.
First of all and related to the alternative to Dreamweaver, I found all the suggestions of all the other answers excellent, but when looking for an alternative to Dreamweaver, the closest application -for me- it was the Amaya Project. Which seems to be richest than other alternatives and a little bit more sophisticated than the Kompozer.
A screenshot from the official web is here for you to see it in action:
Additional screenshots can be reached by clicking the next link: http://www.w3.org/Amaya/screenshots/Overview.html
You may find it a little bit unstable, or at least it was for me but it may also fit your needs.
After playing with WYSIWYG editors, I prefered direct encoding with BlueFish but it is not a WYSIWYG editor.
And about the suggestions for your issue with the firebug I can't say anything, sorry.
Please let us know how did you do if you give Amaya a chance.
After installing Amaya, I find it yet far from stable but somehow it seems to have a better features than other applications, if you consider that other software are simple Text Editors and Amaya is like a WYSIWYG editor.
I tested what you said in your comment and I found that Amaya don't even get noticed that something changed in the files/folders structure/name. Which won't fit your needs related to this.
In the next screenshot you can see I renamed the "resources" folder to "resources1" and Amaya is yet showing it as "resources" and there is no way to force it refresh. Even after restarting the software and loading the project again, Amaya won't notice it.
I am going to follow your question closely hoping somebody come and drop a good alternative.