Ah, yes, resolving this type of issue with a contract packer can be very difficult - it's all too easy to be stuck between various parties who don't really want to do anything that may suggest it's their responsibility...
Nonetheless they should readily be able to give you a summary of the process parameters so I'd keep pushing them on this - if they're not prepared to do so then this in itself possibly tells you something
What is the end product's intended shelf life / storage conditions?
If it's a longer life ambient/chilled product (i.e. shelf life in months) then the rest of the micro data also warrants some investigation, whereas for a short life chilled product it is less critical.
Nonetheless the survival of yeast suggests that the pasteurisation process may have achieved 5-log for pathogens but probably not for spoilage organisms, unless your starting count was ~10^6 cfu/ml yeast!
I think the FDA advises circa 71.1C for 6 seconds to achieve 5-log for salmonella/listeria in juices, but in practice most soft drinks processors I know who are making juice-based products are running at more like 85-90C for 15-30s largely due to spoilage generally being a greater challenge in this type of product.
Presume you've already reviewed samples of the raw materials? Ethanol presence in juices is expected at low levels (should be <3g/L) but higher levels are possible if fruit condition and/or process hygiene during initial processing have been poor. Certainly 66cfu/ml yeast shouldn't be giving you any problem immediately in this respect!
As Sweet_Lew noted, Alicyclobacillus can be a problem in juices, particularly cloudy ones as you can't filter to remove it, and killing it thermally requires a high level of heat to the point that it wrecks the flavour/colour of most juices. Taints from this vary, but "antiseptic"/TCP and "hammy" are two common descriptions so perhaps not relevant here unless the "alcoholic" element is perhaps the former?
It's moderately difficult to test for (won't show on your standard TPC or similar) so if this is a potential concern then you'll need to find an external lab who are familiar with it. You're on the wrong side of the Atlantic for me to make any specific recommendations there, but I'd suggest asking around to see if you can find one that is familiar with the IFU12 method for this.