Okey, for better understanding let's break your post in parts:
So I'm still a bit confused about what to do. I'm only trying to RNG IVs. I've used the 5th Gen Time finder and have got a seed with the required IVs.
This is solved with the post from The Agonist.
It is using what I THINK is the correct Timer0 value.
How many time's did you calibrated your game? BW2 games have a lot of Timer0's, so is heavely recommended to calibrated at least 30 times (yes 30 times) to get a good chunk of Timer0's. To search for seeds you have to use your
most common timer0.
I've used Min/Max frame of 1 so this seed is on Frame 1.
Oh, I have to press B and Y, is that why the frame is advanced by 2?
If you set the min/max frames on the Time Finder to 1, there's no way Reporter will give you a seed on frame 2, re-check this information.
I want a Lonely nature, and have a Lonely Munna with synchronise at the head of my party. Do I need to then put this seed into the main RNG reporter itself?
You said you only wanted to abuse IV's..... anyway. Having a synchronise pokemon does not guaranteed the wild pokemon will have the same nature. Here is where the main window of Reporter comes into play.
On main window, the method you need to choose is Gen5 PIDRNG, input the nature of your synchronizer and remember to select to boxes "memory link" and "BW2" if they apply to you. Now copy/paste your seed and hit "calculate starting frame" and then click generate.
The bolded frames are synchronizable frames, thus they
will always have the nature of your synchronise pokemon, but the only way to know if the frame you choosed is synchronizable is using Reporter.