Here is a modification on iancoleman that you kind of suggested in the other topic & @BlackHatCoiner posted it https://bitcointalk.org/index.php?topic=5342570.msg57185821#msg57185821 - how different that modification would be to the already modified tool you've posted here on my topic?
Theoretically, the first part of the modification should be all that is required... this is the bit that basically bypasses/ignores the checksum (similar to what Electrum does)... You just force it to return true, rather than calculate the checksum and see if it matches etc.You don't want the second part, the change from "mnemonic"+passphrase --> "electrum"+passphrase as that will break the BIP39 generation... but I haven't had a chance to actually test this out as yet... and compare what it generates with what Electrum generates.
Then you did this post in the same topic: https://bitcointalk.org/index.php?topic=5342570.msg57213565#msg57213565
-the 1st tool is the one you have also posted here
- the 2nd tool though is different. Could you I use it for BIP39 Elcetrum seed because you wrote that it bypasses the checksum
No. Because that 2nd tool includes the "electrum"+passphrase modification... so any seed that it generates will NOT be BIP39 compliant. The thing you need to realise is that even if you don't explicitly use a BIP39 passphrase (or the "seed extenstion phrase" in Electrum)... there is a default one that is used... in BIP39 it is the word "mnemonic"... in electrum it is the word "electrum". So, even if you leave it blank, the 2 systems will never generate the same seed from the same 12/24 words.-the 1st tool is the one you have also posted here
- the 2nd tool though is different. Could you I use it for BIP39 Elcetrum seed because you wrote that it bypasses the checksum
or this post from you seems quite appealing too: https://bitcointalk.org/index.php?topic=5107752.msg49651803#msg49651803
Not quite sure how that factors into things? 
Your wallet was an old Legacy wallet... it'll most likely be in the m/44'/0'/0' derivation path... they extra "script_type" value is only a factor when creating newer SegWit based wallets.