Is it ok to have sex the day before surgery?

As long as you use birth control to prevent pregnancy, I see no reason why this should be a problem.

After a mommy makeover, it takes time for the implants to
settle (if you got implants) and it takes time for the swelling to resolve.
This can take up to 6 months so I don't usually recommend any revisions
for that time. Specific questions about problems with the surgery are usually
best directed to the plastic surgeon who performed your surgery. Thanks
for your question!

I can't imagine you'll be in the mood for sexual activity after the operations you describe. Nevertheless the go-ahead should be from your own plastic surgeon.

Sexual activity the night before surgery should be fine. It would be unwise however to become pregnant as a result.

Generally speaking, sexual activity is okay, pregnancy is not ( be careful!). Best wishes with your upcoming procedure.