I think any type of workout is good for you. It might not make you lose fat as much as some intense workout, but it will always make you feel better and it's a good opportunity to enjoy the surroundings and feel present and connected with the nature.
Any exercise will help, of it's adapted to your physical state and capacities. It's better to do a little thing, no matter how small it seems, rather than nothing, because then at least you'll have built the momentum. Walking is fun and relaxing too, and if done in a nice place can help with your mental state, that will also influence your weight. And finally, there is no such thing as without fail : life's like that, sometimes we have the best intentions and we mess up. It's nothing to feel bad or guilty about, and promising yourself to do it without fail is bound to lead to disappointment (and all these bad feelings that makes one unmotivated) the very rare day you can't. Be kind to yourself, and pat yourself on the back everytime !
Yes, maybe. But you should use that as a start, for example, you start by walking 10 minutes, than 15 minutes, but instead of walking more time you slowly start walking a little bit faster, and like this you will being introducing, slowly, running time in your routine, without your body recognize it.
In my point of view, exercising is not enough for getting in shape. It definitely helps you to lose fat, but you must have a great diet as well.It's not needed to choose a complicated diet. Just try to eat healthy foods and cut back on sugar, fizzy drinks, and junk food. Don't forget to have plenty of sleep, and drink enough water!!!
I think it will be hugely beneficial in every way! Not only will it help you shift some of the weight you want to see gone but it will also do wonders for you psychologically! The fresh air, the time to relax and be alone with your thoughts and nature (if you so wish) will hopefully help you feel a ton better! And you get into that routine which you won't want to break.