This is exactly how many on here would structure an ex-eu, indeed many here would build in far less irrops time. Penultimate flight of day from LCY = sensible. Overnight in DUB = sensible. Same airport for TATL sector = sensible. Big gap between arrival from DUB and departure for sunshine = sensible. Take final flight back to DUB = very sensible.

The only thing I would highlight is that you have a plan for getting back to DUB airport the next morning, and that you set multiple alarms on multiple devices, plus organise a hotel wake up call, to ensure you make that first flight.