Staying warm and dry is often overlooked by newcomers. Get some warm, waterproof boots and warm gloves if you don’t already have them. If you aren’t warm and dry you will be miserable no matter how many other tools, toys, gizmos and gadgets you have.
Next is a reliable auger with sharp blades. Sounds like, in your situation, a hand auger and a drill attachment would do the trick.
After that is some sort of fish detector. Whether it’s an old, jerry-rigged circle flasher, a converted open-water graph or a dedicated ice sonar, something to tell if there’s fish below you puts you at a huge advantage psychologically. If your Helix is rated for the cold, you can just rig it on a Genz box ($30) and buy the transducer.