Question: It was discovered that the only way for the demons to take possession of a living person is either through a kiss or a bite. How could Colin have been turned into a demon when he wasn't bitten or kissed?
Question: When daylight appears in the house, Maddie, Colin and Jason reach the front door but stop when Colin says something wasn't right. What did Colin see that made him realise something was wrong?
Answer: A sense that it was too easy to just open the door and leave. Evil is a sore loser and will always have a trick up their sleeve to win.
If you pay attention, you can hear bugs and insects that are night creatures making noise.
Answer: It took Maddie several minutes to climb down to the basement after Colin fell through the floorboards. Those couple of minutes was all the time needed to infect him.
Again, he wasn't bitten or kissed, so he shouldn't have been infected.
That's why he states it took her a good amount of time, as the viewers don't know what may have happened... Plus, technically, he was humped.