Not as regards to consent; there is NOT a clear legal definition for "adult". Age of consent laws vary from state to state. 16 is common. 14 is less common but available in some states. In others it is 13. Under "privacy" arguments, many liberals are trying to get age of consent eliminated altogether or lowered to 12 and in some cases lower. Darth Bader Ginsburg believes that all age of consent laws should be abolished or the age of consent lowered to 8 or 12. (She is on record as having argued such a position for the ACLU.)
This conversation is only about the government regulating what adults can do on their own property. Kids are a strawman, and a lame one at that.
Actually trying to say this is about "what adults can do on their own property" is something of a strawman. The law in question has nothing to do with whether you are on your own property or not. It has to do with whether or not the government can criminalize a particular behavior. Admittedly, regulation of this behavior and enforcement of the law is problematic at best when "consenting adults" engage in this behavior in the privacy of their own bedrooms. But that isn't really what this discussion is about since several individuals conspired to lure police into witnessing two conspiring adults engaging in the prohibited behavior and refusing to stop when ordered to do so.
There is a clear legal definition for "adult," so your use of quotes is interesting. Children do not have full legal rights, and as such the government has the right to regulate certain of their behaviors. There are, therefore, not relevant to this conversation.
What I find "interesting" is that your position appears to be that laws governing sexual activity with children are legitimate because the "government has the right to regulate certain of their behaviors" while I favor laws against pedophilia based on the responsibility of government to protect children from sexual predators.
I didn't say it was "consistent," I said age of consent is clearly defined. Each of the examples you mention is a clear definition of "adult" within those states.
That's why inserting children into this conversation is absurd. It's not about what children do, it's about what adults may do. Trying to make this about kids only plays on emotional fears and therefore makes a rational conversation all but impossible.