Was the fact that Bumblebee and Sideswipe were touching significant? It seemed like they were connected in some way, able to feel what the other was feeling

They have done that before. From Different Applications of Moral Support: Bee put a hand on the back of Sideswipe's neck, sifting through the long strands of his hair to find bare skin before he closed his eyes, lips moving silently as he linked.

Sideswipe has been helping Sam and Bee work out a few... *cough* sensory input issues. (And it's hotter than hell. Just... guh.)