So many good points this morning!
I'm leaning toward someone affiliated with CG rather than with the church, but I totally agree that it was someone who had been in the church before and someone who knew Missy's routine. (Or was told this information by someone else.)
And what a good question - why was perp dry when it was storming outside when s/he arrived at 3:50am? (Didn't the rain let up by class time?)
The perp must have changed into the outfit at the church upon arrival, which make me think s/he changed again at the church after the murder.
jmopinion
I've been thinking about this very thing from the beginning. SUSPECT looks completely dry. Either suspect was there long enough to dry out, parked close enough not to get to wet, rain had slacked up, or changed at scene. It is my opinion that suspect arrived already in gear. Parked close to the building. The manner in witch he/she killed the victim seems impersonal. I wouldn't bet on it being related to GC, or church. More likely something in her personal life. I am nowhere near buying into burglary, as the riot gear is overkill and much more conspicuous than a hood and a ski mask over the face. I think if anything it was to hide characters and or be able to a approach the victim. Or at least in suspects mind that this was the point. As for the tight time line: IMO the suspect expected her to arrive at 4am, thus the pacing up and down hallways. Suspect seemed as if was just killing time. That being g the case, I it has been my opinion from the beginning that he/she already knew what they were there to do. Sticking to just the evidence or lack of should I say. If LE has video of MB's truck arriving from gun store then we know that if suspect vehicle not on video that he/she arrived and left from opposite direction. As for walking through the woods, airport etc. Not likely. I would put my chips on suspect being reasonably close. Local or at best from surrounding area.