The airlock not being in place does increase the risk of infection. I would have given the beer more time in the primary to see if anything unusual started to develope on the surface. Chill a bottle in five days to check the carbonation level and SG. Warm the SG sample to the calibration temperature of your hydrometer to read accurately. Probably no infection if the SG is the same as your FG before bottling.
The airlock popping off and losing some beer is one of the indicators of a fermentation that was to warm and overly vigorous. On the other hand you may just have had not enough headspace in your fermentor since this was a one gallon brew in a one gallon fermentor. How the beer tastes when you check the SG will tell you if fusel alcohols have formed from an overly warm fermentation, if it was to warm. Using a blow off tube for the first few days of fermentation will safe guard your fermentor.
If this first test bottle is okay give the rest a couple of weeks of warm conditioning before chilling another for a couple of days to check the carbonation level.
Let us know how the first bottle checks out.