I don't know what you climate zone is, but it sounds as if is warm and humid. Please correct me if this wrong, because my suggested course of action would be different. I would cut this plant back hard to within 6 inches of the base ie. remove most of the green growth. You could try chemical treatments but without knowing what the specific pests are this would be a guess. You are coming into fall now in USA when most pests will reduce anyway. Most fuschias recover well from drastic pruning provided the climate is not too cold.

I don't see how there could be any connection between mulch and ticks. They are animal parasites. Ants do not live in pine bark but usually nest in soil or decaying wood. They could nest in the soil under the mulch, but not in the mulch.

Spider mites are the smallest of the rose pest and sometimes can't be seen with the naked eye until you notice their webs. This pest arrives in the hot weather and stays on the underside of the leaf sucking it dry. Spray using an insecticide and make sure you get it mainly under the leaves.

I've gotten the caterpillars using my a leaf as their damn blanket a few times, lol. But this one was not that, for sure. It was more of a sticky webbing tad here, a tad there. Ugh, wish I took a shot of it before I started smudging it off. I'm now certain it is from a small brown bug of some sort. It happened again and on one leaf and when I went to smudge that out too, I spotted another brown bug. Hab, would I be able to see a spider mite? Never experienced this so I'm not sure what to look for. Webbing plus deforming the new growth...and a small brown bug. I'd say it was more aphid-like in shape than a spider but the sticky webbing (or residue?) is weird.