You know it all depends on how strict you want to be, in the strictest sense some say that fruits should be consumed in 'mono' or one type of fruit per meal, generally one is not supposed to mix acid fruits with sweet fruits as we have the problem of Sugar possibly fermenting again in the presences of acid fruit. This is much easier than incompatible whole foodstuffs though.
As for lemon or lime some say that those acid fruits are ok to mix a bit. I do not personally mix acid fruit with sweet fruit. Sub acid fruits are ok with acid fruits and sweet fruits. I would follow that rule with juicing also for best results.