Excuse my ignorance but as I look at it Olajuwon has 7 cards in this product including 4 inserts.
The only "team" themed insert set is Starting Five which includes a Houston card with Olajuwon and a Lakers card and Spurs card.
If the question is, why is Olajuwon not included in the series two base Houston set, my understanding has been that the series two team sets were generally guys who had been traded (Charles Barkley is Houston's only series two team member while Robert Horry and Sam Cassel who went to Phoenix in that trade are included as their only series two team members) or signed late and did not have a card in that team in series one. Some were also guys who were otherwise not included in series one but then for some reason deemed worthy to go in series two.
Just to confuse matters, series two would *sometimes* included repeats of star players who were in series one — see Grant Hill in both Detroit team sets — I guess this was to bump up the star power of series two a bit, especially if not many big names guys were traded. (Though series two did have the rookie cards generally).
So, in theory an Olajuwon could appear in series two as a base team card after appearing in series one but there was no guarantee.
As to why no Lakers or Spurs, I guess they had no trades/late signees/whatever that were deemed worthy of including!
Aand a portland promo set — no idea on that one.