For the sake of reference, I've put one of Yasuhiko Yoshikazu's 1980 illustrations for SF Magajin at the top; when it was decided to have the Pair make a cameo appearance in the Crusher Joe feature film in 1983, he prepared the character designs at center: Yuri is somewhat similar to Alfin (of Crusher Joe) in appearance [left], while Kei has a hair style he used for many young male heroes (for example, Amuro Ray from Gundam) [right].
What might have been: Yasuhiko's proposed character designs in 1984 for the TV series, before he went on instead to work on Zeta Gundam
The designs on top are due to Hosono Fujihiko, who had been drawing the Crusher Joe manga since about 1979; notice that Kei has acquired her hachimaki <headband> at this point and that the Angels' costumes are approaching their familiar Classic style [images appeared in a foldout in the November 1986 The Anime]. Under those drawings is Dokite Tsukasa's preliminary character design for the broadcast television series, which is developed from Hosono's work.
The following illustrations are from the Dirty Pair Mook and were done by artists involved in the TV series, OVA, or movie productions