There is just too much to do to even think of writing anything meaningful before Y”T. Who has time to even go over the basic halachos well? So please excuse whatever errors you find here.
There is a machlokes Mordechai and Rokeach whether there is an issur of amira l’aku”m in having melacha done on erev Pesach. I saw the Aruch haShulchan (468:2) suggests that the nekudas hamachkokes is whether the issur melacha is derabbanan, in which case amira l’aku”m is not an issue, or whether it's a d’oraysa (as the Yerushalmi seems to hold). I thought one could explain it a bit differently. Maybe it’s not the chomer ha’issur – whether it's d’oraysa or derabbanan – which is the issue, but rather it’s the geder ha’issur. The gemara (BM 92) has a safeik whether there is an issur of amira l’aku”m only on Shabbos or by other issurim as well, and I believe we pasken l’kula. Yesh lachkor whether the issur melacha on erev Pesach is just an issur gavra like any other issur, or whether the issur stems from a certain kedushas hayom that the day has, like Shabbos? If the issur is like any other issur, then there should be no problem of amira l’aku”m. However, if erev Pesach has a keduashas hayom, then perhaps amira l’aku”m applies as well.
The din is that when shiva ends on an erev Y”T, the upcoming Y”T cancels the upcoming period of shloshim and one can do laundry and bathe and take a haircut even on erev Y”T. Rama adds that this kula applies “samuch l’chasheicha,” only close to nightfall, except on erev Pesach where it applies from chatzos. Why the difference? The GR”A explains that erev Pesach itself is called a moed. To some extend erev Pesach itself has a certain status as a holiday.
The Aruch haShulchan himself adds in parenthesis that the Rokeach writes that amira l’aku”m only applies on Shabbos, Y”T, and chol ha’moed. It seems to me that the point is not that the issurei melacha on these days is d’oraysa (which at least with respect to chol ha’moed is debatable), but rather the point is that these days all have a certain kedushas ha’yom. According to the Rokeach, that ingredient is absent on erev Pesach; according to the Mordechai, it's there.
My son had two arguments: 1) L’shitasi, the Rama in hil aveilus that says erev Pesach does have a special status is against the halacha here where l’ma’aseh we pasken that there is no issur of amira l’aku”m. I don’t think this question gets off the ground. Just because the Rama accepted the fact that the kedushas hayom is enough to push off shloshim does not automatically mean he has to accept that there is enough of a kedushas ha’yom to create an issur melacha. Even among days that share the common denominator of having a kedushas ha’yom, e.g. Shabbos, Yom Tov and chol ha’moed, there are gradations as what that kedusha implies, what nafka minos it carries with it. For example, there may be a common requirement of simcha in all of those days, but there are clear differences in terms of the level of issur melacha. 2) The gem in B”M sets up the safeik of whether amira l’aku”m applies to other issurim as a question of whether we compare those issurim to Shabbos, which is an issur sekila, or not. It sounds like the issue has nothing to do with kedushas ha’yom and everything to do with measuring the chomer ha’issur. This is a stronger argument than the previous point, but I’m always less bothered by the lason hagemara than my son is. I don’t see any problem in saying that the question of whether amira l’aku”m is a function of having a kedushas ha’yom or simply chomer ha’isur is itself part and parcel of the tzedadim of the safeik.