Is it safe to do lap band surgery with a pace maker, diabetes and high bp.?

Generally yes. Usually, these are the reasons weight loss surgery is performed. Obesity leads to these complications. So, surgery is generally perfomed on patients with these conditions. You should undergo an appropriate work-up before your surgery by your internist and cardiologist to make sure you will be able to tolerate the surgery and you are medically optimized for the surgery.
Depends. Your surgeon will send you for a surgical risk evaluation. Obesity itself is the greatest risk to surgery as well as life. Once you have the surgery, diabetes and blood pressure will improve with yweight loss. You will need to prepare, take your medications and whatever else they recommend to optimize your results but yes, you can have surgery. Your risk is there & needs to be managed.
Safe, but not ideal. All operations (band, sleeve, and bypass) are quite safe. For diabetes, we typically see remission in only 10% of band patients, compared to 90% for sleeve and bypass. You should see a doctor who is comfortable with all.