Some very personal (and hence biased) answers to some of your questions. The bottom line is that there is a big difference between the New Hampshire 4,000 Footers and most hikes in the Berkshires. Mt Tecumseh, arguably the easiest 4,000 footer, is about the same as Mt Greylock by the Cheshire Harbor Trail.
Also, my wife (a complete novice) wanted to join me but if she needs to completely outfit with different boots n such from her usual walk in the three season flatlands, she will pass.
It is not just a question of gear, we are talking of a winter hike with 2,000 feet of vertical, which IMHO is
completely different from "her usual walk in the three season flatlands".
How much snow on the trail do I expect this time of year?
About a foot low down, more higher up. How consolidated depends on the weather this coming week, by now I guess the old snow is beaten down to concrete consistency.
Will I need my snowshoes?
See above, I always bring my snowshoes, when the hike involves a single trail and that trail is welll broken I sometimes end up leaving them in the car (and sometimes end up regretting that decision
).
To do Tecumseh, will my usual hiking boots be enough?
Since I have a choice of winter boots I never hike with three season boots in winter. That said, I suspect that, if the day is not too cold, leather boots may do.