Hey Jordan main thing that creates danger with Li-ion batteries is over stressing them, you'll be running a 2S3P pack depending on the capacity of your particular 18650's you can calculate how much power the pack can deliver using Ohm's law. a typical pack like that can deliver 2-4 Amps 700mA will be a breeze. however there are few other things which to consider for example I personally I steer away from BMS's in low consumption devices because they are just useless and consume energy balancing tiny differences between the packs. With low consumption devices you'll never be more than few mili Volts off unless you over-under charge/discharge, Stress them or some are defected.
That brings up another important factor, are these new or recycled 18650's? nothing wrong with using old ones even if they are from different manufactures as long as you measure their actual capacity and they are within 10-50mA/h. If want to make this torch safe and not going to try to boost your friends bike, car, tractor, tank... with it Lol. I would suggest scraping the pointless BMS they are overrated and only beneficial in high power consuming applications.
Search instead for something like 1-8S Lipo Battery Tester Low Voltage Buzzer Alarm they cost less than £1.00 they show you what the voltages are, buzz if Packs differ too much or are running low, you can connect them on a switch and monitor the pack with clear numbers on the display. You'll learn more about their behavior and be more confident on your next project. I'm sure your friend will appreciate the ability to see what the accrual status of charge is, you don't get that with a BMS.
That is what i prefer especially when using dodgy used 18650.
few more quick pointers
if Li-on's are getting hot when charging/discharging with rated current they most likely are developing a partial internal short which will eventually become dead short and is dangerous or fun if in a controlled environment done in the name of science :)
if you charge the cells then leave them not connected to anything for few days the voltage should not change more than 2-3mV (0.03V) if it does they have developed the same condition as above.
the last one is common sense. These batteries are NOT some unstable explosives but do pack a lot of power for their size and if abused will fail usually with a smoke show.
If you are still reading this i hope you found some useful info.
Warning machines don't have brains, use your own when interacting