There are basically two issues which I have not worked out. One is that light sacrifices are the money of the owner. (קדשים קלים ממון בעלים לפי ר' יוסי הגלילי)Plus if one is not able to inherit a sacrifice then it should be the same with maasar sheni (I imagine). And we know that two inheritors can redeem maasar sheni.
What I mean to say is Zevachim page 6 side A. A inheritor can make exchange but not two inheritors. (יורש ממיר. אחד ממיר ולא שנים ממירים ) Not because of owning jointly, but because they do not own the animal at all. Proof: R. Yochanan said a two inheritors of a flour offering can bring it. Why is this so? Is it not the case that only an individual can ring a flour offering? Answer: they do not own it at all. But if so then why can one inheritor make exchange? Because while in terms of monetary value, the inheritors do not own the sacrifice, but in terms of forgiveness of sin, they do.
So my first question is obvious. The second one maybe not so much Still I am mulling these issues over. I imagine Rav Shach must have an answer for these difficulties, if I can get around to seeing what he says.
[I might mention here that exchange of an animal dedicated to be a sacrifice is not allowed. But if one does it anyway, the second animal becomes holy--in so far that it is not sacrificed but is not allowed to be used for work or shearing.
The second maasar can be redeemed by two inheritors even though the same kind of verse applies אם גאול יגאל
אם המיר ימיר
