I have good news for you. I finaly figured how to set Cries for expanded Pokemon. This do not even need repointing of anything. Listen me carefully.
~~~~~~STEP 1 - SETING GBAPGE to work~~~~~~
We need add particle
CryConversionTable=&H1FDE6A
under string of Cry Table.
This give us able to changing cry Conversions.
~~~~~~STEP 2 - FULLY PREPARE OF POKEMON~~~~~~
Be sure that your new Pokemon have everything. Icons, Sprites, Movesets, Evolutions Table <I preffer use G3T to edit first infos about new Pokemon. And Advanced Series for rest of works>
~~~~~~~~STEP 3 - Change Conversion~~~~~~~~~~
After Unown places you can have Conversion number above 1000. Or 0. Change them in case of first Pokemon <In my case it was Origin Giratina to forme change> As I change to conversion number 388 <387 is Jirachi Conversion> I got pointer of Bulbasaur Cry. But do not change cry Pointer there. After change Conversion <Click save under conversion number. And change only conversion> You can Save changes to game.
~~~~~~~~~~~~STEP 4 - Sappy Cry Insertion Method~~~~~~~~~~~~
This method is helpfully. But if you use older cry instering method you can not use it. Therefore you need go to the last string of Cries. Check in GBAPGE pointer of Jirachi Cry.
But i give you for cleary reason Deoxys pointer. 6379B4
Search b4 79 63 08 from start of Cry Pointer. And right pointers which you need edit to give new pokemon Cry. Is start from string 30 3C 00 00. When I test it without any changin. It played Backwards cry of Bulbasaur. But i decide change that string to freshly instered Giratina Cry. <I need to change 30 3c to 00 3c since high quality cry instered using Sappy> After that I save my rom and test in game. Succes. It works. But remember. As I found. Cry Conversion can be posited randomly. Since in first extra pokemon you can give conversion 388. And on the next one 390. Important is that which Particle you change.
I hope that it help you in your Hacks. My Mega Evolutions which I want include to Pokemon Ruby Renev working great. Especialy that ORAS megas like Mega Salamence, Mega Metagross, Mega Glaile and Mega Rayquaza. BTW. I still do not understand why in game is situated Backward wersions of cries. I think that was for fainted cry. But after faint pokemon still have that same cry.