Lol, this is inception :) One of my favorite movies! It is very uncommon that yoiu woulpd hear this phrase but given that I have seen that movie several times and never noticed tells you that it isn't as weird as it sounds. But I recommend you don't use it. Basically, you can think of it like this. Police use bloodhounds and dogs to "sniff out" bombs, drugs, fugitives etc. When they use their scent to sniff, they find what they are sniffing at. So sniff out a job means search for a job, but not necessarily find one. It's just best to not use it because it is a bit weird.

The implied reference is figurative. I picture a dog finding something by smell. The dog doesn't see a goal and proceed straight to it, but goes wandering around trying to pick up a scent. It carries the idea of serendipity, of not being sure what you will find or how you will conduct the search. "I don't know what jobs there are, I don't know how to look for one, but perhaps there will be something in the air. Maybe I will see a 'now hiring' sign, maybe something will give me an idea when I get there." It carries the idea that the speaker is not trying very hard. Maybe yes, maybe no. "Who knows, maybe something will turn up." It sounds natural enough, but it's not a familiar idiom. The simple thing to say would be "maybe I can find a job." "Q. I just wonder if when you want to say "I found a good job yesterday", you can paraphrase it into "I sniffed out a job yesterday"?" You could and it would be understood, but I don't think you should try to add to your vocabulary. The rules about when you can mention smells and what you can say about them are different from culture to culture.

You're right! "Sniff out a job" = "find a job/get a job." It's more of an idiom of sorts. It doesn't actually mean your using your sense of smell to find a job though. It's an expression that alludes to an animal sniffing for prey. So if there's something you want to find, you can search for it which is the same as "sniffing it out." Another example: "If there is any truth to that rumor, Gladys will sniff it out." Meaning Gladys will look and ask around to find out if the rumor she heard was true. Hope this helps! ^^

It is technically correct, but this phrase isn't very common. It might sound strange if you use it, depending on where you go. I haven't really heard it used before.

Oh I forgot to answer the other question. Yes, it sounds natural to me. Except on the past tense sentence. I think you can leave out the "for me" part. Since you're the one looking for the job, it's not necessary to say you found one for you. So it would be "I sniffed out a job yesterday" or "I found a good job yesterday."