The Chainset per se isn't a problem, you just need derailleurs that are compatible with your shifters (and compatible brakes to shifters too).. if its a road bike Tiagra FD it wont work with the MTB shifters you need for flat bars, Different pull ratios (4700 has same pull ratio as 11 spd shimano)
i'd have a very good check of the parts in the shed before embarking on it, could save yourself a lot of time building something that doesn't work very well