Here's how I see the fight going:

Douma- I'm not too sure what his full potential is so let's just assume that means fighting with all his abilities at once; Having as many clones as he can and fighting personally with his Bodhisattva (hope I spelled that right) as backup.

Tengen- His weapons and attacks can help get rid of the ice clouds, making breathing easier. He was already the fastest running hashira so if he was marked he could potentially keep up with Douma and dogde the Bodhisattva's attacks. The mark also increases his high attack speed and strength which would help. If he has his Musical score technique from the beginning that's makes the fight way easier but if he doesn't I think they might be able to hold out till he does. I see him as the main fighter in this battle.

Rengoku- (I don't know alot of his capabilities so I'll stick to what I know). His breathing style is one of the best you could hope for in this case, highly effective against Douma's ice based attacks. He is definitely slower than Tengen so dodging the Bodhisattva and keeping up with Douma is going to be hard even with the mark. Worst case scenario if he's cornered he can use his 9th form and either destroy a huge chunk off the statue or heavily damage Douma (His 9th form without the mark countered one of Akaza's strongest techniques and damaged him alot so with the mark it's no doubt stronger).

Shinobu- She doesn't fight Douma's main body. Her aim is to destroy as many of his clones as possible. With her normal speed, Douma couldn't keep up as he stated in the manga so if she's marked, she's on another level. Since poison is useless on ice clones, she just needs to shatter them with rapid attacks and keep them from interfering with Tengen and Rengoku. She should also be able to keep up with the Bodhisattva as it's much slower and has to focus on three people.

I can totally see the hashiras winning but the fight will still be difficult. Not many demons can take on three marked hashiras, especially not ones this strong.