By the way DDR3 and DDR4 do not really make a big difference yet unless you are buying 128GB of RAM. Don't buy Alienware because DELL are such a rip off when it comes to gaming. The Asus version of the MSI laptop...
Yes prob ,however the closer you are to the max psu capacity, the more load you put on the psu. The more load means a shorter psu lifespan which could damage components. Maybe go for a 750w corsair they are very reliable
https://uk.pcpartpicker.com/part/cooler-master-cpu-cooler-rr212e20pkr2
Reliable,Cheap and one of the most standard cpu cooler
https://uk.pcpartpicker.com/part/antec-cpu-cooler-kuhlerh2o650
Apparently really good but I would research more
The Asus monitor is expensive however has amazing quality http://www.ebuyer.com/695562-asus-vx24ah-24-ips-console-gaming-monitor-vx24ah
If you are looking for something a bit cheaper reliable and quick you should for the BenQ...