Hard to say. For sure, the Alp mountains are no option, actually almost all passes will be closed due to meters of snow.

If you stay on lower altitudes, it's not easy to predict, which conditions you will find in practice. Do not expect any winter service on dedicated cycling routes, be prepared for the necessity to share the main road with cars and trucks.

You can be lucky and find a snow and ice free route like let's say along the Danube river. But it may also happen, that there will be weeks of high snow level and your cycling is restricted to roads with winter service.

Bike parts?
Nothing special - apart one thing: Spike tires. They make you little slower on asphalt, but are absolutely beneficial in icy condition. You will not slip on ice with them at all. On muddy conditions they may also slip, but not as sudden and uncontrolled as on non-spike-tires on ice.

Equipment: Dress sufficiently warm but, not that much, that you sweat too much. Following the onion principle and stripping off certain shells if too warm, is key. It's not easy to find the sweet spot between not to freeze and not to sweat.
Hand cloves can be found within the Skiing equipment of outdoor shops. Dedicated cycling gloves are often not warm enough. Warm shoes and usage of overshoes is suggested.

Where do you wanna stay over night? If you intend to sleep in a tent (campsite or "in the wild") there are certain specific aspects for winter camping to consider.