i5 8250u would be easily the best choice here if light editing, AE, and rendering are your main priorities, as it has 4 core 8 threads vs 2 core 4 threads of the 7200u. That is because what you mentioned as your use cases (content creation activities) are more dependent on core and thread counts.
Regardless Ill list all the pros of the 8250u over the 7200u.
1. 8250u has 4 cores 8 threads vs 2 cores 4 threads of the 7200u (as mentioned before)
2. 8250u is a newer generation - Q3'17 vs the 7200u - Q3'16
3. 8250u has higher single core turbo speed of 3.4 ghz vs 3.1 ghz single core turbo speed of 7200u. Higher single core speed is important for every computer tasks. meaning your experience with a 8250u will be snappier than a 7200u (however, ssds and nvme drives are a factor too, in fact quite a big factor, faster storage improves pc using experience by far)
4. 8250u all core (4 cores) turbo will be higher or almost the same as that of 7200u (2 cores). Keep in mind that the 8250u has four cores to push for turbo-ing at a 15w tdp vs 2 cores of the 7200u at the same tdp of 15w. And at the worst case scenario, 4 cores turbo-ing at the same speed as 2 cores is still a win.
5. 8250u supports ddr4 2400 ram vs ddr4 2133 of the 7200u (this isnt a huge deal but still a pro, however, you might get ddr4 2133 ram with the 8250u. so yea). Also 8250u has 6 mb of cache vs 3 mb of the 7200u.
Im sure there are more advantages of the 8250u over the 7200u but I think these are some of the major ones. Overall, if you think about it, you can upgrade the ram later where as you wont be able to upgrade these cpus on these laptops. So it would be a better choice to have the better Cpu, newer mobo and chipset and later upgrade the ram later. And you should be able to get by fine with 8 gbs of ram. Just add a 4 or 8 gb stick later.
As for the gpus both 940mx and radeon 530 arent great for gaming but can easily do light gaming and less demanding games run fine on both. But, if gaming is a huge deal, the 940mx is a better gpu than the radeon 530. But I have seen plenty of youtube videos of people playing games on the 530 with low resolution and low details.
And yes you will make a sacrifice if you go with the 8 gb vs the 12gb on the 7200u, but the advantages of going with the better cpu just trumps all the other points since 8 gb is totally fine and since u didnt mention about gaming, the slightly weaker gpu will be fine for you.
Tldr; pick the better cpu as its irreplaceable and you can upgrade the ram later. However, you might be fine even with 8 gbs of ram and if not just get an additional 4 gb of ram stick thats supported by your laptop. The lower end 7200u at this time will set you back quite a bit in terms of performance, technology and so and so. Buying a 2 core 4 thread cpu in 2018 is not really worth it unless you are a very basic user who only browses the web and does office work. Just the 4 gb of extra ram and slightly better gpu isnt enough to justify buying the laptop with the inferior cpu. (important! as you will be busy with light content creation, make sure you get a 1080p Full hd screen at least) And overall hardware wise, its all upto luck really, my sister had this fine laptop which just died out of the blue after 1 or 2 year of use(motherboard died), where as one of my acer laptops from 2010 is still ok.