Would this furniture be ok outside when it rains after?

This is semi-waterproof, and it is not recommended to put it outside in rainy days.

Is it possible to order the entire set plus, 1 additional love seat?

Yes, it is. Pls check the listing. https://www.homary.com/item/3-seater-modern-woven-textilene-rope-outdoor-sofa-with-removable-cushion-pillow-in-gray-28731.html

Cocaro 4-Piece Outdoor Rope Weave Sofa Set with Coffee Table in Dark Grey

4.7 513 Reviews

A$ 2,999.99

A$ 3,799.99

Description

Tata outdoor sofa set pairs a durable aluminium frame with handwoven rope weave detailing for modern outdoor living. Including a loveseat, two lounge chairs, and a coffee table, it resists UV, water, and rust for everyday patio comfort.