Point #1 - interurban trail, burke gilman trail, urban hiking. Most day hikes around here don't meet the "mostly level" requirement.

Oh, wait, there might be a few near Mt Ranier, but I think they're more than 2 miles (1 hour) hikes. Google "hikes with kids" for this area, as that's the most commonly referred to level of difficulty you're looking at.

Point #2 - I hear ya. I think I will improve my henchman and call it good.

Point #3 - I'm still sad about not being able to go to Tokyo this year for work.

2. I decided what to be this year when I found a purple satin with black tulle witch hat at Target for $2.50, in their bargain bins. I have other stuff that will match it, so it works. Really, there are a few questions that would need to be addressed, though:
a. Do you want to use stuff you already have? Are you willing or able to buy or make new stuff?
b. What kind of a costume do you want to do? Something topical, humorous, generic, classic? For example, you could dress up as a zombie Tea Partier, which would hit a couple of notes, but may require the acquisition of new-to-you stuff. What do you usually dress up as?