Either go for 8gb or 16gb, 12gb means you'll have one stick not running on double channel and is usually slower, not to mention a odd configuration
Depends on the refresh rate of your screen.
Since you haven't told any prices, Ill throw some models here:
Offerings from MSI with 1050ti's and 8th gen cpus:
https://www.msi.com/Laptop/GS73-Stealth-8RD/Specification
https://www.msi.com/Laptop/GP73-Leopard-8RD/Specification
https://www.msi.com/Laptop/GF72-8RD/Specification
Omen (HP), lot of options, 7th and 8th gen cpus, but most people say these laptops heat up too much:
https://store.hp.com/UKStore/Merch/List.aspx?sel=NTB&ctrl=f&fc_sb_omen_by_hp=1
Dell Ispiron G series, same as Alienwares, but without the horrendous pricetags:
https://www.dell.com/en-uk/shop/lap...-15-gaming-laptop/spd/g-series-15-5587-laptop
https://www.dell.com/en-uk/shop/lap...-15-gaming-laptop/spd/g-series-15-3579-laptop
Lenovo has the Legion lineup:
https://www.lenovo.com/gb/en/laptops/legion-laptops/legion-y-series/Legion-Y520/p/88GMY500808
https://www.lenovo.com/gb/en/laptop...series/Lenovo-Legion-Y530-15ICH/p/88GMY501020
Asus has some alternatives too, but I'm annoyed at them and don't have more time to get you models.
Most of these are customizable, so you can choose your configuration.