@SpudHut
For the Advanced Industrial I do not believe that each advanced plot has a generic amount of item requirements. As I believe for the sawmill it is actually 200 wood to upgrade.
For residential upgrades, you do have to reach a happiness milestone, I believe it's 70 for level 2 and 80 for level 3. As well, your defensive and food needs must be met. A third requirement is that the plot must also be powered in order to level up. The final requirement is time (This goes for all plot types). In general, as long as each plots needs are met, it'll take 5 in-game days since the plot was built before it'll be ready to upgrade. To get to level 3, it's another 10 in-game days. The time requirement also goes towards your question about Advanced Industrial plots.
As far as scrap mods, most if not all will have some sort of issue, either graphical or settler ai, this is because some things were never meant to be scrapped, e.g. the dirt mounds in Sanctuary, you'll get some weirdness in the looks of the ground if you scrap certain places. As well another issue is the navigation of settlers. This is because when you scrap something using most of the scrapping mods, they do not actually remove the collisions observed by settler AI, thus causing them from being able to enter into certain plots that you may have placed.
And since I had already typed most of this before kinggath and Paladin responded, I'll also add a link to the upgrades page on the wiki which you can find
here so that you can view the requirements for all the plots to go along with the full numbers breakdown linked by kinggath.