Since no one has replied, I will give you my thoughts. I am not an expert, you may want to post on the shrubs forum , but these are my thoughts that come to mind...

Do you intend to place these three shrubs close enough together to form a solid screen?

Each type of shrub may have a different rate of growth, so the top of the 'hedge' may be uneven. Not saying it won't look nice, just want you to be aware of that. Unless, of course, you plan to trim annually to keep at a desired height.

Regarding the height, I assume this may be a lower type of hedge as you will have rugosa roses and dwarf elder?

Sounds like it's worth a try. All of the shrubs mentioned are pretty easy care, once established.

P.S. regarding the lilacs, if you are concerned about blooms, with lilacs you have to be careful what time of year you trim them in. Sounds like you may use a smaller lilac anyways, and not trim.