Which of these can be hard pruned?

I'm going for an informal, deciduous hedge near the front of the front yard, parallel to the house front. I bought some shrubs cheaply from the county, but they all get a bit taller than I really want (ideally, 4-5'). Which of these can be hard pruned yearly or biannually in the early spring to keep them small? I've found conflicting information on the 'Net for all of these.

Amelancher canadensis - shadbush
Sambucus nigra ssp. canadensis - American elderberry
Corylus americana - Am. hazelnut

And the final species is Cornus sericea, but I know that can be hard pruned in spring (it's even recommended).

i have tried all three of these, not sure about the pruning , hazelnut is
ok to prune otherwise it would get to 15' , the shadblow may be more
sensitive to hard pruning, one we had died after "bear-pruning" ,don't know if
elderberry would make a good hedge as it likes wet soil. pruning elderberry
is taboo, but it would look nice on edges.

Why is pruning elderberry taboo? We do have pretty moist, clay loam soil, so I don't think that will be a problem.

Thanks for the advice on the other two - I definitely won't try to hard-prune the shadbush then - actually, I'll probably have to find some other place to put it, where its natural size would be more appropriate.

About elderberry, from Native Trees, Shrubs and Vines, (W. Cullina)
"Older canes lose productivity after several seasons, but they are continually reinforced with vigorous suckers...All elders benefit from hard winter pruning every few years...Cut the canes back to they larger stubs or trunk near the ground"
I was curious because I have one too and wanted to double check, plus had this book handy from the library. Good reading if you like natives.

Sambucus nigra, Corylus americana and Cornus sericea can all definitely be hard pruned. On all of these, I would take out completely the tallest stems right to the ground for height control, rather than pruning everything back some. These all resprout from the base freely. You will also get better winter twig color on the Cornus if pruned in this manner.

Amelanchier canadensis is naturally suckering (although not terribly so), but pruning it hard will encourage that trait. You may (or may not) find that it spreads underground faster than your liking.

Sallyg - I have that book! LOL Should have looked there. Thanks!

Leftwood - Thanks for the detailed info. I think I might try to grow the shadbush as trees/large shrubs and use the other species in the hedge. I had read that about the twig color of Cornus sericea. I think I will try hard pruning that one annually at the end of winter, and the elderberry & hazelnut every two years or so, depending on speed of growth.