What are the best soil and and placement options for growing Lilacs?

Lilacs like at least 6 hours of sun daily and they like humus-rich soil. More info here: https://www.almanac.com/plant/lilacs

Daily sun, for sure. Our Lilacs were planted 60+ years and maybe off-shout saplings, as some Lilacs in this town are 100 years+, a man brought them from Europe to beautify the town. The soil is rocky/volcanic dust/sandy base and they thrive at an elevation of over 6,000 feet. Don't ask me why. They bloom once a year. They are the old world light purple. I do have Lilacs in another state at a lower elevation and they are beautiful in the dark rich soil and humid weather, they live in. Lilacs are AMAZING! So guess, I am saying, use the soil you have, visit a garden center, ask questions, have the soil analyzed. If other flowers grow for you, then Lilacs should.

A lot depends on the lilac you plant. Some, the common syringa vulgaris, grow quite large, so they need plenty of room unless you want to spend a lot of time pruning them. But there are many hybrids, in many colors, and some even reblooming lilacs, which are not as large. I also have heard that they appreciate more alkaline soil, but they do seem to grow well here in the east, where the soil is acid.

I just had to add, as I want your to find some flowesr for your garden. You might want to visit your local lawn and garden store to find out what Zone you are in for planting flowers. Or check online for planting zones. The stores will have flowers that grow in your area, read the flower container informational labels or sticks to see what grows in partial sun.. You may be able to grow Iris, Lilly of the Valley, Fern and others. Don't give up, expand your interest in flowers and enjoy them.