You are seeking opinion about:
" What I'd like to know is:
1. Is it that 138 NI applies to Accused #2 and 420 IPC to me, OR both to both of us OR both to Accused #2 who is the only signatory of the cheques?
2. If the documents and signature are indeed proven to be forged, will I be acquitted from the case from both 138 NI and 420 IPC or just 138? "
But Mr. Ezzy, you untill didn't clarified or mentioned:-
(a) The Complaint in question filedby the Complainant, is whether with the allegation for the offence ONLY "U/S. 138 of N.I.ACT";
(b) OR, the Complaint in question is a Private Complaint Filed U/S.200 of Cr.P.C., against You as (A-1) and your relative as (A-2) with the allegation for the offence " U/S. 420 of IPC R/W. Section 138 of N.I. Act "
If you want the correct answer from us, then please clearly mention and reply to the above (a) & (b)
But meanwhile for the clatification of your doubts:-
(i) If the situation is as (a) of above, the Comlaint in question is wrongly registered against you as (A-1), and you can get "QUASH" the complaint against you, by filing a " Criminal Revision Petition" in the Hon'ble High Court of your State.
(ii) If the situation is as (b) the complaint in question, is maintainable against you as (A-1), and your relative as (A-2). But, subject, to the "Evidence", "Relavency of Documents filed" Circumstances and on Facts of the case, thereby you can't escape from the liability & resonsibility.