Inzamam missed the fourth match at Multan due to a finger injury while Yousuf was looking after his pregnant wife and the West Indies ran away with a seven-wicket victory, leaving the five-match series at 2-1.
Vice-captain Younis Khan remains unavailable after his brother's death last week but Pakistan coach Bob Woolmer said his team would go all out to stop the tourists from levelling the series.
"Inzamam has recovered 98 percent and is sure of playing. Yousuf has also returned so we will be going tough in this series-deciding match and do our best to clinch it," Woolmer said on Friday.
Pakistan won the second match at Faisalabad by a narrow margin of two wickets before recording an emphatic seven-wicket win in the third match in Lahore. The first match in Rawalpindi was washed out.
In the latest match, West Indies paceman Daren Powell took three wickets to restrict Pakistan to 209 before Marlon Samuels hit an unbeaten 100 to steer the tourists to victory.
Woolmer said the defeat at Multan was disappointing but the absence of key players allowed some reserves to show their worth.
"We were 2-0 ahead in the series and had the right to experiment and although the defeat was disappointing yet we had some lessons to learn from our mistakes," said Woolmer.
West Indies coach Bennett King was confident his team would end a non-stop three-month period of cricket on high note.
"Hopefully we can come out with a series-drawing match. We found some good form the other night and we are looking forward to this match and it would be a good end to a long tour," said King, an Australian who took over in November 2004.
The West Indies finished runners-up to Australia in a tri-nation series in Malaysia in September and again in the Champions Trophy in India last month.
"We made the final of two big competitions against good sides and our one-day results are encouraging," said King, whose team lost the preceding Tests against Pakistan 2-0.
King also felt the series decider would give some benefits ahead of next year's World Cup, where Pakistan and the West Indies play the opening match in Jamaica.
"It is important that we finish the series on a good note with Pakistan being in our pool. From our perspective, when we played Pakistan in the West Indies last year to where we are now there has been a lot of improvement.
"We are (a) dangerous force in world cricket -- and 'danger' is an interesting word because it means we are not always on top of the tree -- but we are more often than not," said the 42-year-old King.
Pakistan: Inzamam-ul-Haq (capt), Imran Farhat, Mohammad Hafeez, Shoaib Malik, Mohammad Yousuf, Abdul Razzaq, Shahid Afridi, Faisal Iqbal, Kamran Akmal, Rao Iftikhar, Rana Naved-ul-Hasan, Umar Gul, Abdul Rehman, Danish Kaneria, Mohammad Sami, Yasir Hameed
West Indies: Brian Lara (capt), Chris Gayle, Lendl Simmons, Daren Ganga, Marlon Samuels, Runako Morton, Shivnarine Chanderpaul, Dwayne Smith, Denesh Ramdin, Ian Bradshaw, Corey Collymore, Jerome Taylor, Daren Powell, Dave Mohammed
Umpires: Nigel Llong (Eng), Asad Rauf (Pak) and Television umpire: Riazuddin (Pak)
Match referee: Alan Hurst (Aus)