Take this with a grain of salt since I haven't looked into this situation before, but after reviewing Pub 536 I think that your assertion in Question 1 is correct, that you can apply $30k of your NOL carryforward from 2017 against your own $30k of W-2 income and your $20k of S corp loss from 2018 can be applied against your wife's $100k of W-2 income (because the individual tax return on which the $20k loss is first reported is your joint tax return). Schedule 1 will have negative $20k on line 17 and negative $30k on line 21.
Regarding Question 2, you would have to tell TurboTax on the 2017 Net Operating Loss page that you have $30k of NOL from 2017 to apply to 2018. TurboTax will then ask you to provide an explanation statement as to how the NOL carryforward applied to 2018 was determined (that you have $100k of your own NOL from 2017 but the amount you are applying is being limited to 100% of your own income). That will leave $70k of your own NOL carryforward that you'll have to track yourself for application to future years in the same way as in 2018.
