I think piercing the small intestine/jpouch with a biopsy needle would be a no-no.
Also, I would not want the trus device being shoved up there, stretching the anal anastomosis and putting it at risk for tearing.
I would opt for a trans peri-anal biopsy, where they reach your prostate via the area btw the anus and testicles.
Is your Urologist aware of your new anatomy?