Can you deliver a baby vaginally with a rectocele/ cystocele? What are the complications?

Yes. Cystocele and rectocele present no problem to you or the baby for delivery. Vaginal childbirth is probably the biggest risk factor for these problems.
Yes. A cystocele is a defect in the muscle wall in the anterior part of the vagina letting the bladder wall to bulge into the vagina. A rectocele is a muscle wall defect in the posterior part of the vagina allowing the rectum wall to bulge into the vagina. A vaginal delivery is possible because the baby would push these back into place during delivery. A worsening or even tear is possible.
You can. However the rectocoele or cystocoele may get more symptomatic due to the stretching and thinning of the muscular walls especially if a prolongd labor or large baby.