Would appreciate any tips, hints or suggestions for the best itinerary for this trip.

Family lives in Washington, DC, and we need to visit one set of in-laws in Buffalo, NY for Christmas. We then have a wedding in Edinburgh to attend Jan 5. One spouse has approx 190K miles on United, the other spouse has about 90K miles on US. We also have a toddler and intend to all fly together.

Looks like we can fly to either Glasgow or Edinburgh via Newark. A route from Toronto-Edinburgh costs around the same in miles as EWR-EDI would--but, that puts us back in Toronto, and on our return journey, we don't need to go to YYZ; we need to go to one of the DC area airports.

Any good suggestions for a cost/miles effective way to route this? Can we combine miles?