Need advice for removing Cedar trees to replace with Lilacs

[Cityroller]

We have three cedar trees in the back yard that we would like to remove. They are high maintenance trees, need too much water, and now are mostly dead anyway. How much of the roots do I have to remove, and how can I do that, keeping in mind they are inside a fenced yard. We want to replace with lilacs. Thanks.

[tomc]

Behind door number one:
Cut off tree tops. Burn out stumps. Let lay fallow a year or two replant with lilac.
(Less spendy)

Behind door number two:
Cut off tree tops. Chew up stumps with rented stump chipper. Replant with lilac.
(More spendy)

[applestar]

I wonder if area where cedar grew would have acid soil?

...I believe lilacs prefer alkaline...

[Cityroller]

Thanks for replies. Definitely gives us more options.
Cedars don't grow here, I'm told. Previous homeowner put them in.(crackhead)
Now I know why they don't. Thanks.

[tomc]

I wonder if area where cedar grew would have acid soil?

...I believe lilacs prefer alkaline...

Like the riddle, which came first? Acidic soil, or the tree that prefers it. Without some kinda PH test, a big shovel of crushed lime stone should go around the lilac as phrophylaxis