tunnel tenders

Did the Hoosac tunnel and/or the Clinton tunnel ever have tunnel tenders?

Depending on how you define "tenders," yes. An old B&M employee publication -- mebbe from the '20s or '30s -- had an article about two job classifications that have long since disappeared. The first was "Miners," the folks who maintained the non-wire, non-C&S, and non-rail-and-railbed parts of the tunnel. I saw it long enough ago that I can't recall if there was any mention of Clinton or -- for that matter -- the Little Tunnel, Greenfield, or Bellows Falls.
The other job class was "Foresters," not Subarus, but the folks tasked with keeping trees cut low along the ROW to both aid in eye-balling the train for hotboxes and to reduce fuel to limit the possibility of ROW fires.

There also used to be a trackwalker whose sole job was to walk the entire length of the Hoosac Tunnel in both directions. I don't know if that job is still there, it was when I was working for the B&M up until the 1980's.

What about bridge tenders? Not counting durring WW1/WW2.

Every movable bridge would have needed a tender to allow for navigation during train-movement hours. The North Station bascules were/are operated from Tower A, while others would have had a cabin with either dedicated tender coverage or traveling tenders to meet need, with the bridges being left in navigation position except for train, draft, or power movements.