First you have to tell us what camera body you are using. Is it cropped or full frame? Second, are you looking to upgrade to full frame soon? The reason why you're having trouble taking group shots with the 50mm is because you might be on a crop sensor. 50x1.5 = 75. So you're basically shooting close to 75mm field of view. Try taking multiple photos and stitching them.
As for the 50mm 1.4G and 1.8G, they are really cheap and give you subpar results. As unfortunate as it is. My advice is to get the 85mm 1.8G and 28mm 1.8G if you don't mind using primes. If you're looking for a zoom, I really like the 24-120mm F4. It's probably the only zoom i would get besides a 70-200mm 2.8.