Ordering RDp 8.5

Ok, can somebody explain what we shoul dbe asking our BP for...

One (or more) of these?
5733-RDG 5660-RDP Rational Developer for Power Systems Software:
RPG and COBOL Development Tools for i
N/C Registration and 1-year renewal
5661-RDP Rational Developer for Power Systems Software:
RPG and COBOL Development Tools for i
1 year after license
5662-RDP Rational Developer for Power Systems Software:
RPG and COBOL Development Tools for i
3-year registration
5663-RDP Rational Developer for Power Systems Software:
RPG and COBOL Development Tools for i
3-year renewal
5664-RDP Rational Developer for Power Systems Software:
RPG and COBOL Development Tools for i
3 years after license

Or this?
5724-Y99 8.5 IBM Rational Developer for Power Systems Software

Does it make a difference if we download the trial and just need the
license code?

Looking here, what's the difference between the
https://www-112.ibm.com/software/howtobuy/buyingtools/paexpress/Express?P0=E1&part_number=D0C5FLL,D0C5ILL,D0LJVLL,D0LJWLL&catalogLocale=en_US&locale=en_US&country=USA&PT=html

$913 - IBM Rational Developer for Power System RPG and COBOL
Development Tools for i Authorized User License + SW Subscription &
Support 12 Months (D0C5FLL)

$416 - IBM Rational Developer for Power System RPG and COBOL
Development Tools for i Authorized User Initial Fixed Term License +
SW Subscription & Support 12 Months (D0LJVLL)

$1610 - IBM Rational Developer for Power System RPG and COBOL
Development Tools for i Floating User License + SW Subscription &
Support 12 Months (D0C5ILL)

$733 - IBM Rational Developer for Power System RPG and COBOL
Development Tools for i Floating User Initial Fixed Term License + SW
Subscription & Support 12 Months (D0LJWLL)

Ok, I think I understand...the "initial Fixed Term" versions are only
usuable for 12mo...whereas with the others, supports runs out in 12
months but you could legally keep using the software....

Still what do we ask our be to order?
Thanks!