I think a combination of easy listening non-specific music works well, and I always make sure I have some of these in my repertoire for fill-in. Pamela Bruner’s Midsummer Meadow has some nice pieces (‘Gathering Dusk’ especially), as well as Frank Voltz (Summer Rain). And songs like Amazing Grace, Be Thou My Vision, etc. Anything meditative and soothing. For my father’s funeral I paired the Scottish highland song ‘Farewell’ with ‘My Heart Will Go On’. ‘Into The West’ from the Lord Of The Rings is also a nice memorial piece.
If you know the nationality of the family a homeland song is always a nice touch. If the family has an Irish or Scottish background, there are several slow airs that would do nicely, like ‘Land O’ the Leal’, ‘Ae Fond Kiss’, ‘Inis Oirr’, and ‘The Wild Geese’. These songs are nice for any memorial, in my opinion.