Read/heard so many stories about MIL. Whilst I agree that some MILs are a real pain and very annoying, very often however I find the reason for the 'clash' is just because she is your MOTHER-IN-LAW instead of your own mother! Isn't it true?? Just take a look at your point 5 "she keeps calling us at least 2 times a day wanting to talk to my son". What's wrong with that? Can't she talk to her grandson? If it were your own mother calling, I bet you would find it OK. Your MIL just adores your son and your son is LOVED by a granny. Isn't it a nice thing? You don't like it just because she is your MIL or because you've disliked her already - it's not because her being unreasonable... Unless your son finds it annoying to be called twice a day, I don't think you have any reason to dislike it - she is not calling to talk to you but your son.
Some of her behaviour (e.g. 1, 2 & 3) I would dislike if I were you because they are not really nice. What I will do instead of building up some hatred inside me, is, I will, very firstly, express my view to my husband and tell him what I don't like about her behaviour and request my husband to talk to her. If my husband agrees with her behaviour, then I tell him I will say it myself. (Normally, it'll scare my husband and make him willing to say something to his mum as he fears the 'direct talk' between these two women will end up in a horrible mess!) The point is: I don't really make unreasonable complaint about my MIL so 9 out of 10 times my husband agrees with my view and is able to somehow talk to his mum and alter the situation a little bit. Have you tried to talk to your husband first? It would be a lot easier for him, being her son, to talk directly to her.
My MIL and in-laws are very nice people, they all love & adore my son; I don't dislike them but I can't say I ENJOY being with them. Some are their problems but some are down to my own 'perception/principles/personality'. The main thing bothers me a lot is: They are very LOUD people. When they talk, they don't talk but shout. If you don't know them, you will probably think they are having an argument! Being at my MIL's home is a torture (I'm not exaggerating, as you can imagine the environment where 5-10 people shouting down to each other, then with a telly turned up to a very high volume. What makes it worse is there is a "mahjong game" in the background!!! You can imagine the 'noise' now, can't you?) They like going to Yum Cha in a very noisy & crowded Chinese restaurant which I hate very much. And, I don' t like the fact that they put children in front of TV all day or give them portable electronic games whenver they're awake... These things really upset my mood, to be frank. But do they do it deliberately to upset me? Nope... It's only their 'living style', which I cannot agree with. That's why I don't like going to my MIL's home or hanging out with them and luckily my husband fully appreciates it. BUT, I will still go and visit them with a happy face and chat with them nicely (pretend nothing is bothering me) simply because they are my husband's family. I don't want to make him unhappy or embarrass him because of my feelings towards them. I believe, nobody likes to see our own parents be criticised or disliked, particuarly by our spouse. How would you feel if your husband doesn't like your mum? Sure you will be very hurt.
My MIL is a person loves being 'priased' and put in the first priority. And she loves giving opinions. If opportunities arise, she loves to get involved. HOWEVER, she does not have a chance to get too much involved in our household, largely because, since the first day she met me, my husband has told her that I'm a very strong-minded person and have lots of 'principles', which are better not being challenged. Because of that, she is well aware that she cannot change much of my mind and thus she never really tries to cross the line. Does she grumble behind me? Of course she does...but so?!
My piece of advice to you is:
(1) Whatever you don't like about your in-laws, talk to your husband first (of course in a soft way, not a hostile way) stating the reason why you don't like their behaviour. Be reasonable! You can't just tell your husband that you don't like his mum without a good reason, right?! Do not try to deal with the situation by yourself.
(2) Try (I say try because I know it's not easy but at least you keep trying at your best) not to dislike them too much as the dislike feeling will only drag you down and affect your reasoning power so soon you will only see the bad sides of her and become very 'subjective'.
(3) Whenever she gives advice/order, etc, just say YES then carry on with your way of doings. No need to argue or reason with her - waste of time.
(4) Or, the last resort, just ignore her, politely (which means not pulling a horrible face in front of her).
My MIL sometimes gives some advice which I do not agree, I will, either stay silent in which my husband understands the signal and will say something on my behalf to his mum, or say YES then carry on with my own way. What can she do at the end of the day? Very limited, as long as you & your husband stand on the same line and be firm. But, whatever you feel about your MIL, don't forget, ALWAYS BE POLITE AND RESPECTFUL.