I use them for sea fishing, my local tackle shop does two sizes, mini and larger ones. I can use them whole or cut into strips. Whether they would catch Pike I don't know but why not try them. Maybe two rods one with the squid and see how you get on. I imagine mounted on some sort of pennel trace and used like a spinner would be more productive, a pike or a perch may just instinctively lunge at one. As a dead bait, they smell a lot so could be more attractive in drawing a fish in than say a smelt which has less scent. Worth a try I would have thought especially as you say your usual dead baits are in short supply. Food is food to a hungry fish and an easy meal of squid might just work, I think they are full of amino acids as well, not sure of that one. Just googled it so there you go, what a clever species we are, we are certainly not doomed..
The result shows that squids contain non-essential amino acids, namely aspartic acid, glutamic acid, serine, glycine, alanine, and tyrosine. According to figure 3, the highest non- essential amino acid in squid is glutamic acid containing 2.07% for fresh squid, 8.61% for dried squid, and 12.13% for paper squid.