Your second problem is a common feature of LaTeX when you have lots
of pictures and not many words. Basically it found there was not a
neat way of displaying the pictures amongst the text without either
having a title in an odd looking place or a mostly empty page in the
middle of a chapter.
I suggest you try a couple of things. If you really want the pictures
to be with the text try changing ALL of the pictures to be placed
"Here if possible". I Don't recommend using "Here definitely" unless
it is a last option and note you might get some empty looking pages
appear at the slightest modification of any text.
Otherwise give into LaTeX and admit it is right. Insert a clear page
at a convenient place. This will prevent it being used by text so
some of your pictures will collect on it.. ie they'll catch up with
Note you can always refer to the page number the figures are on
automatically (on the reference pop-up box select the option
"<reference> on page <page>")