Miscellaneous thoughts, all MOO:
1) I don't think BG or the victims are dressed inappropriately for the weather. Low 40's is a temperature that midwesterners adjust their outerwear for, especially teenagers. BG looks to be wearing a light jacket over the hoodie, certainly appropriate for such temperatures. Abby is in a light jacket only, not uncommon at all for someone her age in such temps. I don't at all think this is an indicator that BG isn't local. In fact, I would say it indicates he's used to this climate. Keep in mind also that BG may have been planning to be outside longer than just a couple hours, and the temps drop quickly in the evening here.
2. Springtime in Indiana means soft/wet ground, especially in an area with water. It is logical to think LE was able to locate at least some footprints suitable for casting. Knowing the footwear isn't enough to identify a killer in and of itself, but it could be another valuable clue to help distinguish the countless guys that look like BG in wardrobe, size, and stature.
3. Last year, we had a teen in our town leave a suicide note. Within two hours of entering the house (he wasn't inside), LE had completed a very detailed forensic analysis of his computer, providing much information. With the amount of horsepower LE has assigned to this case, I think it's safe to assume they had every ounce of information from all electronic devices in short order. I recognize there are messaging apps that don't provide information easily and that a perp could watch SM anonymously, but if this was a catfishing ruse, MOO is that LE would be aware of that early on.
4. MOO is that BG is extremely familiar with the area. It isn't a place someone just happens upon, and given the state of disrepair the bridge is in, it's unlikely a person unfamiliar with it would just waltz across it. I also wonder how long the horrific events lasted. It is pretty dark here by 6:30 this time of year, and a person unfamiliar with the area would likely struggle to find his away around in the darkness. Look how many people are struggling with location/direction in the area with the various maps that have been posted.
5. In one of the videos I watched regarding the area around the bridge, I observed a couple of areas similar to a viaduct of sorts. It's the type of configuration I have observed homeless people use a makeshift place to live. I'll try to find it again and post pics. Personally, in MOO, I don't believe he's homeless or a drifter, but if he is, he may have holed up in such an area.
6. MOO is that LE has DNA results if they are collecting from others. The most concerning thing in this regard is that it implies there is no match in the database. If true, that is terrifying.