What functionality of RadEditor are you looking for that you wish to 'attach' a RadEditor to all of these textboxes? You can definitely use RadEditor as
a textbox, as seen here:
Also, you can use a shared menu for all instances of RadEditor to reduce the markup you need, like in this demo:
As far as spelling, you have a spellcheck built into RadEditor which you can use, so if you have a shared toolbar type deal like in the tool provider sample, be sure to include spellcheck in your tool set.