Can I reheat roast potatoes? I'm making Heston Blumenthal's roast potatoes, but I need my oven to finish sous-vide prepared spare ribs as well. The potatoes need well over an hour, the ribs around 40 minutes. The long times both need makes it impossible to prepare both dishes sequentially.

Can I make the roast potatoes a few hours before and reheat them in the oven right before serving?

If not: would having the spare ribs and potatoes in the oven at the same time influence the flavour of either (or both) dishes?
There should be no flavor contamination between the potatoes and the ribs; so you can start the potatoes and put the ribs in later on.

You could start the potatoes in advance and pop them in a really hot oven to get them hot and crispy again. (that is what I would do).