Morena
We have a family trip coming up in January, DUD CHC AKL PVG LHR IAH AKL CHC DUD. This was booked through grabaseat as an AirNZ codeshare with BA, although it sounds like that route may not be going much longer.

On NZ 289 I'm in Z for AKL PVG, and on BA168 I am in I. Which is nice. I'm *A GE but have no status for BA.
However, Mrs B (Elite Partner status) and the little Bs (both Jade status; little Bs sounds a little pejorative and who am I kidding, they are both 6 footers these days) are in Y....

I have put in my 2x RUs for Mrs B to move from Y to business AKL to PVG, and have EAPDUs in for the kids from Y to premium economy. We will do the same on the return via IAH (I should have hit my Elite anniversary by then and been RU replenished).

The kids have a number of questions about this (!) which I'm not entirely sure I can answer...
1) I'm assuming there's no APD earn on the BA legs?
2) We should all be OK for the lounge in AKL (as much as ever anyway) but do we get any lounge access in PVG (because codeshare)? Sure I will get access as in I for next leg but presumably +1 at best for the lounge? I'm assuming I'm either sitting by myself in the lounge or joining the family in the terminal... it sounds like neither of these options are particularly great but we are there for 4 hours or so.
3) Am I right in assuming that any RU or EAPDU that go through only apply to the AKL PVG leg and will not carry over into the BA flights?
4) 3 of 4 of us are veggie. Does veggie meal requirement prevent or reduce upgrade chances as the meals will likely need to be brought up a cabin? I have been upgraded from Y to PE before but had the Y veggie meal plated up in PE, which was fine, but presumably more of a hassle for the crew?
5) Does having different upgrade types on the same ticket reference reduce the chances of getting upgrades granted?
6) on the return leg in IAH, again I'm in J and everyone else in Y. Last time I went that way in J I had access to the Polaris lounge, but I'm pretty sure the rest of the family won't get in there. I think there are other *A lounges (United) but again I think that it's a one guest only for Elite members, and Mrs B as Elite partner won't count as Elite outside of AirNZ owned lounges.

By context we have never managed any EAPDUs ever... but the upgrades thread looks like there's plenty of people out there who are consistently fortunate/wise in their flying dates. Maybe we are just unlucky, but I wonder if it's the meal requests and the multiple people reduce our chances? On the other hand I got an op-up once from LAX to ZRH from Z to F for no obvious reason, so it can't be an absolute no-no.

I have had a look at the BA lounge access thread but unsurprisingly that's divided up by BA status and flight class which doesn't apply easily to my usage.

So there's a whole heap of questions, sorry - I have had a good trawl through the forums but man this flight stuff gets complex eh!

Thanks in advance for any help
Cheers
b