A nice pair of dark green, navy blue, gray, or black flats or dress shoes are always a great option for a funeral

Germain, Fresh Lemon & White Cranberry Juice $19 APERITIVO Aperol, Fresh Lemon Juice, Domaine Chandon Brut, Fresh Blackberries & Raspberries $16 BLACKBERRY CLUB Lyre's Zero Proof London Dry Gin, Muddled Blackberries, Fresh Lime Juice, Simple Syrup $14 PINEAPPLE PICANTE Pineapple Infused Cdigo 1530 Blanco, Picante, Fresh Lemon Juice, Orange Bitters $21 PRIME MANHATTAN Woodford Reserve, Carpano Antica Vermouth, Amaro Nonino, Rosemary Grapefruit Peppercorn Bitters $20 CUCUMBER GIMLET Bombay Sapphire Gin, Muddled Fresh Cucumber, Fresh Lime Juice $17 ESPRESSO MARTINI Ketel One Vodka, Vanille de Madagascar, Espresso, Kahlua, Served Black or with Cream $19 WHISKEY CLOVER Gentleman Jack Whiskey, Hennessy VS Cognac, Honey Water, Fresh Orange & Lemon Juice $18 NOGRONI Lyre's Zero Proof London Dry Gin & Vermouth Rosso, Giffard Apertif Syrup $15 PANOMA Seedlip Notas de Agave, Fresh Grapefruit & Lime Juice, Sparkling Grapefruit Soda $16 PREMIER COCKTAILS Fashionably Prime - A refined twist on the classic Old Fashioned

More about playsuits and summer clothes
If youre going to a gathering that requires the fanciest of the fancy attire, you want classic Oxfords (or opera pumps for braver guys)
Thanks to The Row, caged flat sandals have become a bonafide fashion essential
As you mentioned in your question, the fall wedding youre attending as a guest is in October outdoors (for the ceremony)