Don't put matching pairs at the door unless the front of your house and the garden in front of it are also all perfectly symmetric, with everything in identical pairs and geometrically proportionate (same size, shape and distribution of windows on each side of door, garden laid out in matching rectangular beds with straight paths etc). Instead, use asymmetric balance, with something like a small shrub and medium shrub together on one side and a larger shrub on the other, that by itself looks as important as the other two together.

Dwarf Alberta spruce is popular, hardy, compact and slow.

Great area, I can picture a winding or curved path from the doorway and small conifers, perennials, small shrubs on both sides.

I am sure there is a lot of choice for your zone. Maybe try for a variety of conifers (blues, green, golden). Not every plant will stay small forever, though if you go for slow-growing ones they only grow a few inches per year. You may also try small shrubs which tolerate annual pruning to keep within a certain size.

Mugo pines can work good, as long as you go with a named cultivar where you know the growth rate. I have a bird's nest spruce that's very slow growing as well. Colorful leaf plants like emerald gaiety euonymus might be slow growing enough, or at least tolerant of annual trimming to keep within bounds. There is a vinca called 'illumination' that has wonderful green/gold foliage. That's more of a groundcover but don't restrict yourself to just conifers. Somewhere in there too, maybe find a purple leafed perennial or small shrub.

Having mentioned the above plants, they are slow growing for me here in zone 3, but will likely grow faster in your warmer zone. Just thought I would give you some ideas as you really have a chance to make something unique here.

Glen

Glen and Bboy, thank you for the suggestions. There is nothing formal about anything related to me, so I like the idea of the informal or unmatched front. I was also envisioning a winding path from the door. I plan on getting started on this this spring. Glen the plant information was very helpful. It seems I don't know much about plant names, thanks again.

Maybe later you'll want to hire a garden designer or horticultural consultant to help get things go in the desired direction.