When you stop zoladex- the average time it takes for your ovaries to wake up and ovulate and start a period is about 5 months. So half of ladies will be quicker than 5 months and half take longer.
If the break is only 3 months - then take that break at most - you are likely to have one period in that time towards the end of the 3 months by most lasies won't even have had 1 period in that time, so it is certainly worth such small odds.
The dodgy thing is that you don't know how long it will take to start up again or when a period will arrive, so it is a bit of a waiting game. You might be lucky and have advanced warning if you generally do feel when you ovulate then the pain of the pop a couple of weeks before the 1st period may be all the signs that you get.
Once yo have had the 1st period after stopping - you can then go on BC pills back to back for a while to give you a break using different chemicals.
It is certainly a good idea to stop zoladex after 6months- that is the maximum recommended in a life time unless you are taking the drug for cancer- in which case your life time expectations are much shorter anyway.
The reason is because the drug causes your core bones -spine pelvis and skull to become much weaker over time and the longer you are on the drug the more the bone density diminishes. So stopping and trying something else as and when your periods to return is going to give your body a better chance to recover some of that bone desity loss.
I think your surgeon has given you very good advice- and stopping the zoladex with just a few months afterwards till surgery is a good idea. You won't restart your periods as soon as you stop- or at least most ladies don't - (I did - but that is quite rare judging by feedback on this forum -) most ladies are still waiting for the periods after several months. So you don't need to start taking back to back BC pills until you are ovulating again. It is probably a good idea (painful though it will be) to have one period in between zoladex and the BC pills -just so you know you are working ovary wise- and to clean out that old lining that has been sitting in there for several months by that stage.
That's up to you, but if it were me- i would want to know the ovaries had woken up properly as some stage after stopping the drug.
If by any chance they don't wake up (it is very very rare) then you need to be started on HRT to top up the body with the hormones it will need for heart health and bone strength.
See how you get on once you come to the end of the line with zoladex. then make a decision on BC pills or back to zoladex....once you have had your 1st period after and got it out of the way.