Both will be drinkable. As simple mistakes go, there are plenty you can make that will render a beer undrinkable. These could/probably will both turn out great, though they will not conform to a particular style you were intending.
As for the yeasts I've seen Wyeast London used for both NB and Oatmeal or Sweet Stouts, so you should be ok there.
Up Next - Elephant Rider IPA
Primary - SpaceGrass APA
Primary - Dos Coronary (Two Hearted Clone)
Kegged - Worst Ever Hefe (seriously, it's terrible)
Kegged - Black Umbrella RIS