1. The spike "theory" is in no way true. Spikes have been documented to become 140-160" class deer. The message that gets messed up is if you have 2, 1 and 1/2 yr old deer (both being bucks) the a 3-4 pointer will out pace a spike the rest of his life.
The take home message about spikes is, if you are seeing a bunch of them, you have too high of a deer population in the area. Spikes generally represent a buck that (as a fawn) was dropped much later in the year. This means that in their whole first year of growing they didn't get as much food as the others (closer born to winter = less food available) and that is why they could only make spikes. If you are seeing a lot of spikes, start harvesting some does.
2. This is not true in any sense. Deer can move in herds (often does do) but fawns (like young children) will often group together too. I have killed several does that were by themselves. Does can often be pushed out of a herd by other does if she is in heat and they are not. Also, a rutting buck could run a doe away from others. The best way to determine is to get you a good pair of binoculars. Also, after you have watched deer for enough time, you can kinda start to tell the does from the bucks by just their behavior and body shape.
3. In my opinion I don't think that a gut pile will spook a deer. I normally don't gut my deer on site just because I like to get out of the area and let the deer settle down after hearing me drag the deer and smelling me walking around. However, I have seen deer walk right up to/right past gut piles and never give them a second glance.
The only reason I would have a slight hesitation about gutting a deer by your hunting spot is that you do run the risk of attracting predators. This can end up making deer spooked and cause them to be a little harder to hunt. I have gutted a deer and then coyote hunted over that gut pile to kill a few.
Hope this helps! Good luck with your hunting and if you have any more questions, just ask