Re pt.1, with EY forget about Y+ (doesn't exist) as well as the low cost upgrades (they charge almost as much as full redemption). But if you're going to travel with them then for any chance of upgrades you'll have to be with EY guest.
If you're price sensitive then you'll need to look beyond EY and either take QR, BA, VS (from DXB) among others. Fares ex-AUH as you'd expect are quite dear on EY.