First, if you are coughing, can you ask them to try a sputum culture from your cough first? Or at least explain why they want a biopsy instead?
As for the 3 antibiotics, I won't say it's easy, but it can be done. Yes! to the probiotics - I take them every other day.
My biggest problems have been weight loss with lack of appetite and fatigue. If you watch the NJH video on food and nutrition, she gives good tips. Three of my strategies are Carnation Instant Breakfast in my morning coffee (I can't face food first thing in the morning), protein powder in smoothies and sauces, and eating something every 1 -2 hours until 8pm. I grab cheese, 1/2 a high protein shake, some smoothie (I make them by the pitcher), part of a Lara Bar, a piece of fruit...
To manage the side effects of the meds, I take all 3 at bedtime, at least 2 hours after last food and my other evening meds, with just a sip of water. I tried taking one in the morning as recommended, but it made me so sick there is no way I could stay on the regimen, so this is my compromise.