narrow the region you want to edit (https://www.gnu.org/software/emacs/manual/html_node/emacs/Narrowing.html). Then use iedit as usual
You can also iedit-toggle-selection to toggle certain selections before text replacement.
You can navigate between selections. See code from iedit-lib.el,
(defvar iedit-lib-keymap
(let ((map (make-sparse-keymap)))
;; Default key bindings
(define-key map (kbd "TAB") 'iedit-next-occurrence)
(define-key map (kbd "<tab>") 'iedit-next-occurrence)
(define-key map (kbd "<S-tab>") 'iedit-prev-occurrence)
(define-key map (kbd "<S-iso-lefttab>") 'iedit-prev-occurrence)
(define-key map (kbd "<backtab>") 'iedit-prev-occurrence)
(define-key map (kbd "C-'") 'iedit-toggle-unmatched-lines-visible)
map)