any variation on this will be rather tactical during the day from a light perspective. Anyone within smelling distance can recognize the smell of fire rather quickly regardless of what you are burning. At night using a small fire in a container such as this in a wooded dell would be mostly hidden from view but again the smell of fire is distinctive and would carry. Small fires such as this won't make much visible smoke. In a true E&E scenario you should forgo wood fire completely and use fueled fire sparingly. An alcohal stove such as the trangia or soda-can stove would be much more stealthy but less easily created from expedients.

For stealth use shelter rather than fire for warmth and chemicals rather than boiling for sanitation. Fire is not stealthy. Fire is visible, smells distinctive, isn't naturally occuring, leaves tell-tale signs that are detectable after you have moved on, etc. Fire is extremely helpful and should be something you are always capable of but it is also not appropriate in an E&E scenario. I would revise this if you are in an urban / industrial setting. In scrap lots, junk/yards, and other urban settings where hobo's and homeless gather you could get away with setting up a decent fire and camp right along with the other squatters and you would be as inconspicous as they. Of course then you would have to deal with them.