Lets try and cover these points one at a time
Even without faults you will get a small spark/crack when connecting the LiPo battery, this is due to the capacitors in the ESC’s (and maybe other components) being at low resistance due to being discharged. They will draw a very high current for microseconds whilst they charge. If this concerns you somebody makes XT90 connectors which ‘suppress’ this surge, these are next size bigger than XT60’s though.
No, you would not die !! the lipo voltage is either 12v or 16v (3S or 4S fully charged. You need about 60volts DC to kill you. (trust me I’m an EV engineer )
Sounds like the bullet connectors shorted the LiPo + and -.
A LiPo battery can provide high currents very quickly and melt connectors, may even burn you if you are careless
Check your wiring and soldering very carefully for good bright joints, look for splashes of solder across connections where they should not be.
This hobby has the potential to do damage and cost money, ensure you have the basic skills, or a friend who can help.
No, when you connect the LiPo various components will put a load on the battery and draw current (about one amp total) i.e flight controller, camera, video transmitter, LED’s and the ESC’s will draw a little current for their logic circuits to work.
Only when the FC tries to power up the motors will the ESC’s draw (more than an amp or two) high current.
Yes, when powered ESC’s will beep, but this is low current for a few seconds, it could be as high as 2-3 amps.
Hope this clarifies