I would need more info and honestly the best place for this info is your local garden center .

Before planting anything I’d review the bed. It’s too narrow at present to contain more than a strip of annuals or small perennials. Anything big enough to provide privacy would need the bed to be a minimum of twice as wide and preferably wider. The cedars, lilacs and Forsythia are overcrowded and will outgrow their space in no time so, personally, I’d vastly expand the whole area and spread your existing shrubs throughout it with reference to their potential size. There’s probably no need to buy any more shrub material, just fillers. You also appear to have wires to take into account.

For any further plant suggestions people need to know your geographical location. Once we have your location plenty of contributors here are in a position to help with local knowledge.

Eta just realised you said you’re in Ontario.

Sometimes the worst place for this type of advice is the local "garden center".... Local independent nursery perhaps.

But yeah, agree with Floral -- bed is too narrow for much of anything.

i agree on bed depth ...

but also.. i might collect plants in august.. but i would hold planting until september.. when the nights are reliably cool ...

and get the fence painted before you plant everything... unless you live in my world of letting vertical wood turn a natural grey ... paint/stain once.. paint for life ... pshaw on that .. lol ...

take the name of any plant to a search engine.. and then flip to the images side.. to see what a plant will look like in the future ... even better if you have cultivar names ... e.g. forsythia: https://duckduckgo.com/?t=ffcm&q=forsythia&iax=images&ia=images

though they can be beaten back thru very aggressive pruning .... to get the height you need.... they will be taking up a lot of ground space

ken