Preface:
Thanks to my countless hours spent surfing through 2addicts posts over the years, I've been able to really surprise people with how much I know about my car (especially as a female). And I'd like to thank all of you experts for helping me avoid getting taken advantage of when it comes to repairs. While I can usually find answers searching through past threads, I can't seem to find what I'm looking for today.
Situation: 
I took my car to get serviced after seeing smoke from the engine body area and the tech said there was a lot of oil in between the bell housing and oil pan. They cleaned it, sprayed it with powder spray, and test drove it but couldn't find the leak. They're saying it could either be an oil pan gasket or rear main seal leak and want me to drive it around for a little to try to recreate it.
Just ask your damn questions: 
1. Are either oil pan gasket or rear main seal issues common/expected for a 2014 M235i?
2. I don't see any oil leaking on the ground or out of the exhaust, and the check engine light is not on. Is there anything else that could be causing oil leaks in between the bell housing and oil pan?
3. I read in a past thread that
"All rear main seals 'leak' very very little. I would call it sweating more than leaking." Could this be true and the oil has just collected over the years and I shouldn't worry?
4. I read about a product called BlueDevil Rear Main sealer. Does anyone have any thoughts/experience on this for a M235i? Note: This is not a cost issue, I really just don't want them to tear my baby apart if it is a rear main seal (Think of it as someone trying to find alternatives to open heart surgery).
Looking forward to your responses!