I solo backpack all year round in Labrador, Canada, including winter, and then mostly snowshoe hiking. Practical safety always applies: a means to signal if necessary (DeLorme InReach for me and pen flares); suitable clothes and shelter to stay warm and dry (especially in winter if you get storm bound for days); and food. To accomplish the last two my base weight goes up considerably in winter. Coldest I've slept out in is -24C/-18F without wind chill.
As to avoiding number 1, the need to signal for help, your risk increases dramatically when you lack local knowledge of where you are hiking, especially in remote areas where there are no other hikers or passers by and you are plodding around on snow in places you have never been. Going solo will always entail greater risk, and consequently demand greater care and caution if you wish to be safe.
The gear you need is very context dependant. What works in a New England winter might be wholly inadequate in northern Canada, and vice versa. Likewise between trail hiking and backcountry expeditioning.
There are no magic bullets.