Conjecture
We know from the order of names in Robert senior's Will that Robert junior was the eldest son, followed by George then John. So the fact that George is listed first, and separately from his siblings, in John Robucke's Will tells us that his brother Robert was not included in this arrangement. (This might suggest that Robert junior was the son of Robert senior's first wife, not Alice.) His brother John, if included, would have been listed after George. But the fact that John is not mentioned, and that Alice's remaining children are not named, might suggest that this phrase "every one of [the rest of] my wyffe children" refers solely to George's sisters. If that is the case, then the bequest of 6s 8d (one third of one pound) to each of them could indicate that there were three daughters, adding further proof of the existence of Anne as the youngest of them.