Thanks, Nan.  

Yes, we do think that DYS is a possibility, but of course we don't know that for sure.  Honestly, I go through periods of thinking that she's definitely at that level and periods of thinking that there's just no way.  Like I said, she's been confounding me.  
The tester we will be using will probably be a student under supervision of an expert wrt testing gifted kids.  It costs much less that way (and we genuinely cannot afford said expert's regular fee).  I don't know if we'd really get to talk to the student ahead of time.  I guess I do need to make a list of questions to ask.  
I wonder if anyone would recommend the WJ for a 5-year-old.  I'll admit that I'm biased against it, probably for no good reason.  But it does seem like she'd have more of a ceiling.