You keep Bled, Booker, TJ & Len.
and it's going to take longer than 2 years to be "contending caliber"....unless you mean contending for the 7/8 seed in 2 years. In case, our starting 5 is...
PG Eric Bledsoe
SG Devin Booker
SF Ben Simmons
PF *Anyone but Keef
C Alex Len/Tyson