My plumeria are doing really well indoors over the winter, minus these tiny bugs (one is suspended in center of this photo). Teeny tiny orange-brownish things with tiny webs (most noticeable when they're between branches of inflo). Are these spider mites? Dragging the plants outside and spraying them down with insecticidal soap isn't curbing the issue. Is there something systemic that I can use?

I'm frustrated, especially since these stupid things are now surely inside our house. Any help is appreciated!

Matt