Both will work for you, with the i7-7700HQ requiring less power.
Both will require you to use Windows 10, and nothing lower
Both are soldered to the motherboard, so you will not be able to replace them later should you fall in love with another processor.
You can compare both here: Intel® Product Specification Comparison
Personally, I would buy a laptop that supported dual/switchable graphics for the work you will be doing. Get something with an nvidia or amd graphics processor so you will not be dependent on Intel graphics alone. You will be glad you did.
if you had to choose, which one would you buy? Would you buy i7 7700HQ?
You wouldn't buy the i7-7700HQ just yet, If you haven't bought it already I would suggest you don't. The new 8th gen H series is just round the corner