I went through the post and summarized everything for readability, maybe the guide can start with this. If anything, it helped me get clarity on what needs to be done. I hope twistedsymphony and s8n doesn't mind. Please feel free to let me know if there are any corrections or clarifications needed. Working on the game list next. I hope posting cart list for possible conversion won't piss people off.
Every ROM for Pochi Nyaa is encrypted, we need Decrypted P-ROMs, V-ROMs, C-ROMs, M-ROM and the extracted S-ROM (derived from the encrypted C-ROMs)
For conversions PROG-BK1 is the most versatile donor PROG board (will work for any conversion that's possible)
CHA boards CHA256, CHA256B, or CHA512Y will support any possible conversions.
Since this is such a small game you could also Use PROG-TOP, PROG-GSC, PROG-GSC3, or PROG 4096 as well as CHA 42G-3, or CHA 42G-3B
Any other donor boards are not recommended as the PCBs used plated through-holes which makes de-soldering difficult.
impossible conversions are one that use C-ROMs and V-ROMs larger than what can be burned to 27c322 (32Mbit) and 27c160 (16Mbit)EPROMs).
OP went with World Heoroes 2 Cart, PROG 4096 B and CHA 42G-3
For the PROG Board, use 27c800:
Set you jumpers on PROG 4096B similar to Super Side Kicks 2:
https://www.mvs-scans.com/index.php/File:Super_sidekicks_2_set4_b1_front.jpg
Split decrypted V1 ROM into two files and burn to 2x 27c160 for V1 (lower half) and V2 (upper half)
For the CHA Board CHA 42G-3:
No jumper changes needed
The S-ROM is always burned to a 27c301 (aka 27c1000 "non JEDEC", buy any brand other than Marconix)
The M-ROM is oversized, you'll need to burn to a 27c040 (aka 27c4001)
Wire mod needed on M-ROM EPROM
Lift pin 31 (A18 ) before soldering it to the PCB so that it doesn't make contact with the 5V connection
run a wire from pin 31 (A18 ) to A18 on the NEO-ZMC chip (Pin 9).
This needs to be done any donor PCB. Based on WH2 scan, this is required
https://www.mvs-scans.com/index.php/World_Heroes_2
C-ROMs
As this CHA board only supports up to 27c160 sized EPROMs (16Mbit), and the size of the Pnyaa C-ROMs is 64Mbit
It needs to be split twice requiring 8x 27c160s
C1 will be split into 4ths and become C1 C3 C5 and C7
C2 will be split into 4ths and become C2 C4 C6 and C8
Op went wit the following chips
P-ROM x1 ST M27C800-100F1
V-ROM x2 ST M27C160-100F1
C-ROM x8 ST M27C160-100F1
S-ROM x1 ST M27C1000-12F1
M-ROM x1 ST M27C4001-10F1