Hi Vij,
I have implemented the same scenario.
you have gathered almost except Service rev req. first let me answer your questions.
1) 1. How to change the existing FYV?
I suggest you not to change the fiscal year variant For ex (AA) use the same Fiscal year variant (This is the best approach) create a shortened fiscal year variant as you mentioned.
Goto OB29 and change the period end date pattern
2) 2. Should there be a year close on 28th Feb, 2014 with the existing FYV?
yes this is possible, nothing will impact if you close the period on 28.
3) 3. Effect on the Open PO, Production orders, Sales Orders and Deliveries.
Open PO and Production and Sales orders are always based on Dates and not based on periods. and more over settlements can be executed at anytime.
other things you need to consider.
Asset Accounting is the major impact
Service revenue recognition is also impacts a lot.
Before you implement i suggest you to contact SAP for help because this is critical change and you will see data inconsistencies.
for asset accounting config done in OAVH t code. and also used some other t codes to update period end dates.
if you have any questions, feel free to ask.
Regards,
Sree