Hi there,
My opinion is that even if you decide you yourselves don't need/want one, take the opportunity during reno to be able to add one later (electrical,etc.). They can be used in any sink, any # of bowls (although I am not certain about the use of disposals if you have a septic system- I'm sure someone more knowledgeable can pipe in on that).
If you do decide to get one make sure you read up and get the right # of horsepower and other features that meet your needs. Another consideration is the size of the unit itself given the space available for it. If you use the search function on this forum you can find several threads on the topic.
Even though we compost, we use our disposal a lot and would really miss it if we didn't have one. We found a good price on our Waste King on Amazon.com. We've also had Insinkerator brand in our old house and liked that as well.

Having grown up without one, I now can't imagine not having one. We do some composting, although not as much as I would like yet...still a work in progress for us. But, find that there will still be plenty of use for the GD.

In our current kitchen, we have one with our single bowl sink (we're keeping the GD but getting rid of the single bowl sink). So, to answer your question, yes, you can absolutely have one with a single bowl sink.

If you do get a single bowl, particularly a smaller one like what you mentioned, I suggest trying to find one that has the drain to the back and side. Our current sink has the drain centered, which means that more of the cabinet is taken up down below AND even more annoying is if I have a pot or pan soaking, it's hard to use the GD.

You don't need to get a special sink to use a GD, but you do want to do some research about which GD will work best for your needs. Our old one was LOUD! The new one is quite quiet (all things considered).

Yes, you should. Although it's better to compost most of your garbage, there will always be those bits that run down the drain or shouldn't go in a compost pile at all. For that stuff, it's so nice to hit the disposal switch and have it gone. I'm assuming that you don't enjoy using your finger to swipe the stuff out of the strainer and throw it away ;)

While you're at it, investigate getting an air switch to operate the disposal. This button replaces an electrical switch on the wall near the sink. Installed, it looks like this:

When you see a picture online it will show all these parts

The two extra buttons are just color options. The box plugs into your disposal and the tubing connects the box to the button. Very simple, very inexpensive. I second the idea of looking for a sink with a rear corner drain if possible. One downside to a disposal is the real estate it occupies under the sink. If you can get it to one side rather than the middle, that's a bonus.

If you currently do not have a garbage disposal and are switching to a deeper than builder grade sink as well, you may need to open the wall and lower the waste arm so that everything drains. Water doesn't flow up hill. It's not that big of a deal to do, but it is one extra thing to think about. Also, if you are on a septic, you can install a disposal, but you should only use it clear out the yucky bits and not to grind up vegetable matter to wash down the drain. Composting will take care of most of that, along with most of your paper waste and your septic (and your garden) will be happier.

Hmmm... I am thinking of removing my garbage disposal when we do our new sink counter. I don't like having one. To me, it is like having a mini septic tank right there at the bottom of my sink. I don't like clean it. I don't like the noise it makes. I know it isn't good for the city sewage system. We don't use it much anyway. I have added a basket because I find something I can see easier to clean than that weird hole in the sink.

My DH and I do not agree on this. So, I've told him that he has to keep it clean to MY satisfaction. We'll see how that goes...