I will build team around him but base on modern football, that means I will not use 4-2-4 which is considered to be his best formation for him. I will use 4-3-3 instead of 4-2-4 to gain advantages in midfield and possessions, which are very important in present days. In fact, Eusebio could be built in a lot of different ways and formations ( both back 3 and 4).
-Iniesta and Falcao have excellent playmaking skill, which is very necessary in this set up and both have played supporting roles for their biggest stars in their teams. Iniesta for Messi and Falcao for Zico. Both have decent work rate, which require a lot in modern football too(especially 4-3-3 ).
-Benzema would be happy to play as Eusebio's supporter or side kick, he had experienced playing this role for almost 10 years with Ronaldo. His football intelligence and unselfishness would make him get along well with Eusebio.
-Balanced fullbacks, Maldini and Carlos Alberto. Maldini will be more defensive oriented in this set up and the reason I choose Maldini is in real life 60s Benfica's left-back Fernando Cruz was more of a defensive full-back. On the right side, Carlos Alberto will be more of a balanced/attacking fullback , inspiration to pick Carlos Alberto was from Dominico Cavem 60s Benfica's fullback who was more of an attacking fullback but still provided defensive solid.
-Gk and Cb: It's up to you.