Ikki is similor to Saga in several aspects.His skill Poenix Flaming Wings(Hou Yoku Ten Sho) can break stars into pieces,which is similor to GalaxianExplosion.Poenix Phantom Fist(Phoenix Genma Ken) can cause mental damage,which is similor to GenRou MaOuKen.What's more,Ikki is the coolest and most masculine bronze saint while Saga is the coolest and most masculine gold saint.Ikki is the tallest bronze saint except giant Geki, while Saga is the tallest gold saint except giant Aldebaran.Although Kurumada set Ikki as Leo zodiac sign,I think Gemini Ikki should be also cool and attractive.

Capricornus is considered as the most loyal saint of athena,while Jabu is considered as the most loyal Servant of Saori Kido.Unicorn Gallop and Jumping Stone are alike.Jabu uses unicorn's horn as his weapon,while Capricornus has Excalibur.So Jabu is the most suitable successor of Shura.

Scorpio uses animal poison.Ichi uses animal poison,too.Snake is always mentioned in the same breath with scorpion.So Ichi is the most suitable successor of Milo.

Aries cloth and Pisces cloth are the most feminine gold clothes except Virgo cloth which is belong to Shun.So the most suitable gold cloth to Marin and Shaina should be these two.
The skill of Aries,Starlight Extinction and Stardust Revolution are related to stars.Marin's skill Ryūsei Ken(Meteor Fist) is also related to stars.Mu and Marin are both good friends and teachers of the bronze saints.They both excel as the fleetest saints.
Pisces uses poison of plant.Shaina is snake,which causes association of poison.Shaina and Aphrodite both have cool temperament,while Marin and Mu both have warm temperament.So I think Aries Marin and Pisces Shaina are more suitable.

After the war againt Hades,all saints died except ten bronze saints and two female silver saints.They are the most suitable choices to reform 12 gold saints.I wish Namco to release updates to add Nachi,Ban and Geki.Then we can make mods of Cancer Nachi,Leo Ban and Taurus Geki.

The problem is the heights of different chars. In some cases it would be almost impossible to fit\match the bodies with the armours

Some settings of Kurumada is random.Sometimes his original settings of some saints' sign astral is not so important.Pisces cloth will cry if it's worn by ugly Ichi,won't it?

I haven't the picture of Aries Marin.I can only post a picture of Sagittarius Marin.

I think there are two attractive directions to mod this game.
One is to make more beautiful and sexy female characters,let the available female characters dress on more clothes.Women would never feel that they had too many clothes.
The other is to let more reasonable successors dress on the gold clothes.When we match them,we should not only consider the original but random settings of sign astral of Kurumada.Kurumada is not going to let Jabu,Ichi,Marin,Shaina dress on gold clothes,just as he is not going to let Muu,Ardebaran,Aioria,Shaka,Dohko,Milo,Aiolos dress on Surplices.But is a cloth which is as cold as the Aquarius cloth useful to Ichi?Only the Scorpio cloth which is full of poison can strengthen him.We can even imagine that Ichi learn to play Scarlet Needle and Antares,because they share the same type with Mellow Poison.But we can't imagine that Ichi learn to play Diamond Dust and Aurora Execution.If a saint can't play Diamond Dust and Aurora Execution,why does he dress on the Aquarius cloth?I think the type of skill should be the most important reason when we match the silver and bronze saints with the gold clothes.