In process of buying a 2012 X5 xDrive35i: oil/coolant issues

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I am in the process of buying a 2012 X5 xDrive35i with 82k miles.
There is a fairly significant oil leak under the hood, a shop says its the gasket between oil filter housing and valve block, and also between oil filter housing and oil cooler.

Doesn't sound like too big of a deal, however;

With the engine cool, I stuck a straw into the coolant reservoir to pull out a sample. There is a layer of oil sitting on top of the coolant. The coolant appears to be a yellow-green color (thought its supposed to be blue?).

How serious is the issue? Should I walk away? Do I need to check the oil? Inside the oil cap looks ok...

I'm ok with spending some money fixing a few things... maybe $800. But I need to know if there is any permanent damage to the engine.

How should I proceed?
Thanks.

Edit: added attachment image