Can this be used on a leather couch following the use of the leather oil?

We actually recommend that our Leather Salve generally be used before Leather Oil, but also note that you might not need to use it at all if your leather couch is relatively new. The Leather Salve is the best product for reintroducing nutrients to severely dehydrated leathers. Our Leather Oil is great for newer leather because it will help keep the leather hydrated, but is easier to apply than the Leather Salve. The more often you refresh the leather with our Leather Oil, the less likely it is that the leather will ever dehydrate far enough to necesitate using the Salve.

will it work for lambskin?

Yes, our Leather Salve works great with lambskin leather.

I have a pair chapped cognac and a pair acorn brown. Will this restore without darkening much or is there a different product i should use?

Our all natural Leather Salve will darken and restore the color of leather. After about a month the color will lighten. This is what I would use for flat shiny leather. If it is nubuck or suede I'd use our Suede Cleaner. We have more information on each product and photo tutorials on our website if you have more questions.

Will my leather shoes still stay white

Probably. It's clear. But does have yellow tint in tin. Perhaps over time they may become discolored. Used it on purse, knife sheath, and wallet, none white. Great product!