Hi, sanderskn,
As the members in your party range in age from 2 1/2 to early 60s, I have some recommendations for your time in Nairn:
Dolphin watching below the Kessock Bridge in Inverness
A visit to the Black Isle Wildlife Park in North Kessock, which would be ideal for your son. Part of it involves a petting zoo.
Dolphin watching along the Moray Coast, especially Spey Bay.
A walk along the Ness Islands
Although it's a fairly touristy thing to do, a boat cruise on Loch Ness would appeal to all involved, especially if you tell your son to keep an eye out for "Nessie."
A visit to the Elgin Cathedral, which is a fascinating ruin.
Be sure to visit the Museum of Childhood in Edinburgh. It's along the Royal Mile
Also, the People's Palace in Glasgow is a great place for people of all ages to learn about the history of the city. It also has a small botanical garden and a nice café. It's my favorite museum in Glasgow. And best of all, it's free, as are most of the museums in Glasgow. Check out the huge gold statue of Queen Victoria in the fountain across from the entrance, and The Templeton factory across the way.
Glasgow Cathedral and the Necropolis are also very much worth a visit. If you're visiting the Cathedral first, you can walk across the footbridge to the Necropolis.
As you'll be in Glasgow on a weekend, a visit to the Barras would be a lot of fun for everyone. It's a hodge-podge of tackiness, huckstering, and some of the best entertainment you can get for free. Also some of the most amazing junk stalls you'd find outside of a flea market. The Barras are open Saturday and Sunday. Afterwards, you could have a meal at Café Source, which is in the basement of St. Andrews Church (St. Andrews in the Square). It's a short walk from the Barras. Or you could have a short (or long, depending on whether your son is walking or in a stroller) walk on Glasgow Green.
I'll probably think of more, but for now, best wishes for a fun trip!
Mike (auchterless)