While I like the extended exposed copper of the footprint (I should, I use it myself ) it does cut down on the available space and extends the space you need around the footprint to route things, and you might need a bit more space than āusualā, and once you get used to soldering the things (or progress to skillet/toaster reflow) you can go back to the easy to use one
All things considered, your board is pretty damn good ! The only thing Iād say is make sure you solder the 7-seg display on LAST otherwise youāll never get to the socket
The darlington wonāt affect it. Itās simply a way to drive higher currents from a small signal input. Your LEDās are way lower than the current it can drive. Your 150
One thing I would point out is to have 1 decoupling CAP per IC.
Also check your track widths on the power and ground lines. These really need to be much heavier. Their size should be based on the current capacity but for you little design, I would go with a 1mm (40mils) track width.
Not sure how to drive Eagle, but if you need to have VIAās on the power tracks, set the software to use larger than the ones used for the other tracks. I usually make the via the same outer diameter as the power track and the holes half this. I am sure others will have a view on this.
As your board only has the 1 SMD you can just hand solder this. I wouldnāt go to the expense and hassle of an oven for 1 connector.