The best time to tear up a parking lot is 10 years ago.

The second best time is today.

Peaches,

Again, I'm trying to come at this from an educational perspective (not directed at you, but whoever will read it), as reclamation is my area of expertise.

do people even want this reclaimed? You’re going to have a shit load of stake holders that all have diffent visions for the land in question What was the pre-disturbance ecosystem? Yes, I do. OP asked what I would do and my answer is tear up/redevelop based on proximity to urban centers

Here, I'm getting at that you need to consider the sale of the land, the zoning, and neighbourhood and municipal government interests before you can change what land is used for.

Do you have a plan to unify this patch of land with other ecosystems like it?

No. We’re going to have a new ecosystem comprised of scarred earth that will suffer from erosion for a decade or so before vegetation takes hold.

This will take a lot longer than you'd expect, given the soil is compacted and devoid of nutrients. I've seen compacted pads/parking lots remain mostly unvegetated 20 years later. Look at abandoned wellsites, and seismic/cutlines for other examples, and those examples have surrounding seed sources.

There is no topsoil, so what are you going to use for a growth media? Usually it’s organic amendments mixed with the subsoil.

There won’t be topsoil until naturally deposited organic matter decomposes and mixes with minerals at the site. This could take awhile.

Again, this is going to take a very long time. Soil takes 200-500 years to form 1 inch of topsoil under ideal conditions. Most plants need a minimum of 10 cm of topsoil to grow. If you use amendments, you can definitely speed this process up. Look at oil sands or mine site reclamation. They can get some pretty solid establishment after 10-20 years. Despite this, they don't expect to achieve a late seral stage community until 100-250 years out.

how much will it cost to amend the subsoil with organic amendments (in lieu of topsoil) and where will you get it from?

Not applicable. We’re doing acclerated erosion until natural depostion and decomposition of organic matter can bring vegetation to the site.

I don't see how erosion is supposed to be a soil forming factor. natural deposition and decomposition of litter from established plants can definitely build soil, but it takes time. Alders are really good at this. They have nitrogen fixing capabilities, and can grow in some absolutely dogshit soil conditions.

what are the application rates of the amendments that ensure plant growth? " parking lots are compacted, so you’ll have to get equipment to decompact it. This will require a minimum of two passes with a dozer ripping to 50-100 cm in depth What planting or seeding rates are you going to use?

not applicable

yes, applicable. you need to prepare the reclaimed soil profile so that roots can penetrate and you've established soil drainage, lest your plants drown from ponding water.

Re: weeds - there's regulations around some of them (noxious etc). so you'd be forced to treat them. Clover and dandelions is a far cry from whatever pre-disturbance or naturalized system people may want.