Safe to charge the battery on the car or use jump leads if done "properly"
If not done properly any surge or short may cause the fuse link to blow.
Again, removing the battery for bench charge and refitting will cause no issues unless you mess up and short out.
I have done the above hundreds of times on the 350s, 370s and GT-Rs without issues, but you have got to be diligent and careful.
Good luck.