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There is no regular fertilizer guideline for Boxwood.
The most reliable guide is a soil test to determine if there is a Nitrogen deficiency.
The first signs of a deficiency is yellowing leaves, generally will start on the bottom branches and work it's way up.
If you determine that your plants need a fertilizer, use a granular urea 10-6-4 or something similar.
Scatter around the drip line as this is where the most active roots are.
Do not over fertilize, as this can lead to root burn.

Here are some links to help you.

https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/boxwood-winter-protection.htm
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/boxwood-care.htm
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/trimming-boxwood-bushes.htm

This could be caused by environmental issues, pests or disease.
You will need to inspect the plants more closely.
It's a good idea to remove and dead material and clean up the area around the plants and dispose of the plant material.
Here are some articles that will help.

https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/yellow-or-brown-boxwoods.htm
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/boxwood-blight-treatment.htm
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/diseases-affecting-boxwoods.htm

I'm sorry, but you can't get rid of that smell. Most likely the type of boxwood you have growing near your home is English Boxwood (Buxus sempervirens 'suffruticosa'). This particular type of boxwood has a reputation for that 'cat pee' smell. Some people actually like the smell. Ironically, English boxwood is the more expensive type of boxwood to buy. There are many other types of boxwood (such as the American Boxwood and Korean Boxwood) that don't have that smell (or any detectable smell at all). The only suggestions I can make is to maybe keep your windows and doors closed (especially on hot and humid days when the English Boxwood smell is at its strongest), get some sort of room deodorizer to mask the smell, or try to convince your condo association to replace the English boxwoods with another type of boxwood or other hedge.

You can attempt a rejuvenation prune, which can help open up the plants to allow sunlight and air flow. If no part of the interior is producing leaves, this may leave you with nothing.
Early Winter is the best time to do this type of prune.
Boxwood are slow growing.

Here are some links with more information.

http://www.clemson.edu/extension/hgic/plants/landscape/shrubs/hgic1061.html

https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/trimming-boxwood-bushes.htm
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/boxwood-care.htm

This cultivator of Boxwood are excellent for small hedges.
They have a moderate growth rate and have a nice dense evergreen growth.

Keep a regular watering and fertilizing schedule the first season to encourage good strong root systems in the plants.

Let the new plantings become established and growing well before beginning to prune. Pruning can be done any time of year, but avoid in the fall.

https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/trimming-boxwood-bushes.htm

You'll want to be careful how much you trim off, unless you want very dense regrowth in the pruned area. This article contains tips for pruning Boxwoods:

https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/trimming-boxwood-bushes.htm