More on Shavuot and its lambs... If older animals were brought - it's a dispute, whether they would count for the offerings of Shavuot or not. That is, if the intent is correct; if not, then not. Also, if the kohanim made something pigul - then that is invalid, even if it was done inadvertently. Plus, a new mishnah - with more on essentiality: the daily offerings and the additional offerings of a given day, when both are not possible, for whatever reason. Also, in the case of missing an offering, the ability to make it up later in the day was real, unless there was intent to miss it. But if inadvertent, fulfilling the obligation for the offering later on was acceptable. Likewise, for incense. Plus, the order of precedence in the case of a community that could only offering one of the given offerings.