You can do it without the hook tool but for a couple bucks it’s worth having. It’s easy to cut with a straight cut aviation tin snips. You will have the damaged pieces to use as guides on how to cut the replacements. The nails are not supposed to be hammered tight the siding just hangs on the nails and that allows for it to expand and contract with the temp. if you are careful you can unbutton the siding off the nail heads and not pull them. (sometimes)
Did you have the grill too close?