There's some good info on SOH and battery health on the Flip the Fleet site - see https://flipthefleet.org/2017/nissan-leaf-check-your-battery-before-buying/
85% is close to the point the battery will drop to 11 bars - the link above discusses this.
We bought ours at 12 bars and around 87% SOH (I think), and it dropped to 11 within a month or so of buying it! I used to worry about this, and regularly used LeafSpy to track it - but for me it took away from the pleasure of driving the car. Ever since I gave up worrying it's been a much more relaxed experience.
Some will say a high SOH is a must, but as with any purchase it'll depend on so many factors and how you rate them: your budget, the range you believe you will require, the prioritisation of battery health over other features - for us, we were happy to accept a slightly lower SOH to slightly mitigate the higher purchase price of a car with (I think) eight airbags.
If you're needing to max out the charge every day, or have limited ability to regularly charge the car, then a high SOH may be really important - but then again it would make more sense to also look to a 30kwh model. But I reckon for most people it's not a truly big issue - there are some with early (ie pre-2013) Leafs with relatively limited range, but they still work for them.
One thing on the BT in our 2013 - it is somewhat fussy with my wife's phone, and this wasn't a once-off as it was the same with her previous phone! Annoyingly, she usually has to manually force the phone to connect, whereas it's always been pain-free for me.