Roses in your zone normally need to be pruned way down because of winter damage. You then should get some new shoots from the base. The guideline is to prune down in sections until you find white, rather than brown or tan, center pith. See the discussion currently on the Antique Roses Forum and other current threads about bad canes.

It is not easy to grow good hybrid teas in your area. You might want to stop and chat with those who are growing the plants you admire. Have you protected the grafts against winter damage? If not, you may be looking at rootstock suckers.

I would suggest trying the somewhat hardier Buck roses. Some that are easier to grow and disease resistant are Earth Song, Prairie Harvest, Winter Sunset, and Quietness. These can be ordered from boutique nurseries like Roses Unlimited, Chamblee's, and Antique Rose Emporium.

I have the same hesitation, in pruning my younger bushes, because the standard advice to prune away anything smaller than a pencil-size diameter and any "twiggy growth" would leave me with pretty much nothing on some of mine (like my relatively new Marie Pavie and The Fairy). I've assumed that that advice referred to roses that were more established, three years or more. As Michaelg says above, with winterkill you have no choice--but other than what you HAVE to prune, I don't think there's any harm in being conservative on pruning the young'uns, because they need to spend their energy building up a big root system, rather than trying to regrow canes and what little structure they managed to put on last year. Seems unnecessary to set them back. That's just my own theory, though--maybe others have a different view.

It depends on the root system and the condition of the canes. Winter damaged canes can really set a plant back. Worst case, canker can set in and kill the plant. But, if the canes are healthy, I generally leave them, unless I think the root system has grown enough to support a bigger cane in its place. Is the plant winter tender?--if so, I'd probably leave a woody cane, as I believe they are more resistant to winter damage. But, in much of Connecticut, roses are moving out of dormacy, so it is getting too late to dig them up without impacting the Spring bloom.
The biggest difference in the size of plants is blackspot control--if you can keep the leaves healthy the entire growing season the root system will grow enough to support a big plant (for its variety). Plants that lose leaves will stay small.

They are one or two years old. Were they own-root plants or bare-root grafted plants. If grafted, the roots are actually now going to be about four years old and you can prune them down. If own-root, the roots are small and can't support larger canes yet. I don't prune own-root roses at all for a few years because I want them to develop as plants first.

Leaves are little engines that convert sunlight into plant. So let them grow.

You're colder than we are but you should be able to tell what is dead at this point. If in doubt, leave it alone for another week or two. Wherever you see little red "measles" on the canes, that's likely to be a new cane.

And be sure your plants have enough sun and water. If the soil is tough and poor, that could be another reason your plants aren't growing well. If so, I'd amend the soil rather than simply dump fertilzer on it.