Character mistake: When the now human Borg children are sculpting, one of the children tell Seven he made a cube that's precisely 1/1,000 the size of a Borg vessel. Borg Cubes are described as 3 kilometers in length, if not bigger. 1/1,000 of that would be more than 9.8 feet in length. 1/10,000 the size would have been a more accurate description.
Character mistake: B'Elanna replicates and assembles a television from 1956, including a remote control. Tom however says they didn't have remote controls in the 50's. The first wireless remote was invented in 1955 and the "Zenith Space Command" (a remote looking similar to the one in use) came out in 1956, which fits the timeline. Tom is vastly aware of 1950's technology (he seems to know when the television remote came out) and wouldn't make that mistake or B'Elanna would have corrected him given how much research she had to do to set the whole thing up.