2017MBP vs 2018MBP vs AIR18

[Strym]

hi!
i need a little advice on which Macbook to choose for my future as a developer, hopefully.
I have these to pick from. (Price is due to 20% discount at my local store)
Tasks i plan on using it for:

• General websurfing, Netflix and Youtube
• Photoediting, some raw.
• Programming (Starting school, mostly Unity, C# , iOS apps/games)

PS: is the new air able to run any of the blizzard games if turn all my settings to low?

• Macbook pro 2018 TB 13 inch - Price: £1399
• 2.3GHz quad-core 8th-generation Intel Core i5 processor
• Turbo Boost up to 3.8GHz
• Intel Iris Plus Graphics 655
• 8GB 2133MHz LPDDR3 memory
• 256GB SSD storage1
• Retina display with True Tone
• Touch Bar and Touch ID
• Four Thunderbolt 3 ports

• Macbook Air 2018 - Price: £959
• 1.6GHz dual-core 8th-generation Intel Core i5 processor with Turbo Boost up to 3.6GHz
• Retina display
• 8GB 2133MHz LPDDR3 memory
• 128GB SSD storage1
• Intel UHD Graphics 617
• Touch ID
• Force Touch trackpad
• Two Thunderbolt 3 ports

• Used Macbook pro 2017 TB 13 inch - Price: £1150
• 3.1GHz dual-core 7th-generation Intel Core i5 processor
• Intel Iris Plus Graphics 650
• 8GB 2133MHz LPDDR3 memory
• 256GB SSD storage1
• Retina display
• Four Thunderbolt 3 ports

Thanks in advance!