Halacha has specific instructions on who to distribute an estate to. The eldest child, if a son, receives a double portion. The rest of the sons receive a single portion. If a person wishes to distribute it differently than Halacha specifies, he needs to make special instructions.
I dont think according to Halacha you can say all the children (Boys and girls) get an equal portion , I think this is assur even if you want it that way (Especially to avoid your heirs fighting over an estate…Not a pretty picture)
My understanding is that if a father wants to leave assets to a daughter, he gifts it to her the moment before he passes. I think that’s how a Halachik will works. CYLOR
The problem is that secular wills – by their rules – take effect – Li’achar Misah. And at that point, the dinim of yerusha take effect – So a regular secular will violates the dinim of yerusha.
There really isn’t that much of a problem with distributing assets among your children al pi halacha. the real difficulty is is how halacha and the laws of the State of New York deal with your wife. According to law, you cannot disinherit your wife. she is entitled to half of your estate. This is in contradistinction of what halacha allows which is only the amount stipulated in her cesubah (including any tosefta thereto.). It would be an exceptionally wise and thoughtful choson who makes some stipulation in the tosefta to hte cesubah dealing with this issue. Maybe mesadrim Kidushin ought to think about this in addition to what they usually think about .