Answer to question 1: Yes, this is the age of whine. For us, I'd just tell our kids to stop whining, and usually they'd speak normal after getting corrected. If they were particularly persistent, I'd ignore them until they put two and two together and would ask or speak in a normal tone.
If you do the "ignore" method, be sure to give them a break the first few times, so you can establish the rule. For instance, you get a whiny request, after a series of other whiny requests, such as; "Can I have a cookie?" you could respond, "Not if you keep whining." Then they change their tone, and you follow up with, "If you whine again after this warning, I will not respond to you until you learn to ask properly.
Believe me, it works and gets results after a while. I have found kids resort to whining because they learn through trial and error that it wears us (parents) down into giving them what they want, even if it's not what you want. They know if they pester us enough, we'll give in to get them to stop. You'll just have to be more aware of the circumstances when they start whining and try to counter the behavior in the future.
One other thing I learned about whinning... many kids programs on PBS of all places, have main characters that whine alot. Big culprits include Caillou and Max from Dragon Tails. I noticed after my kids would watch these two shows, the whining would begin. I nixed those shows from our viewing list. That seemed to help alot too.
Answer to question 2:
Try a kitchen timer, or potty watch (find them at www.onestepahead.com). By giving her a cute kitchen timer (many of them look like animals, cars, flowers, etc.) or a potty watch she can wear, giving her a sense of control (which we know toddlers are all into that!) and she'll be able to take responsibility for going to the potty on a regular schedule. The watch can be programmed to alert her every :30, :60, or :90 minutes with a cute little tune. Or you could set a kitchen timer and let her keep it with her throughout the day. If she might tend to lose it, just keep in where she can see and hear it.
The second benefit of a timer in this situation is if she still hasn't learned read her body signs that she needs to go, she will learn because she will be going to the bathroom, whether she needs to, or not, on at regular intervals. In a short amount of time, she'll learn to read her body signs, and will soon (usually on their own) stop using the timer and just go on her own.
The third benefit is, if you're not handy, she'll still get prompted to go to the bathroom, giving both of you a little more independence.
Good luck, hope this works out!