First example:
The cream should always be in the changing spot in the first place, and should always be replaced at the changing spot if it's moved from there, or just buy cream for each room in which you might conceivably change a baby. Even if you rarely use cream, buying a few extra tubs or tubes isn't going to break the bank. Same goes for wipes.
After you have set up your home with practicality in mind, you could say - 'You can handle that, right?' to your DP.
For foody questions - get organised, place a running list somewhere in the kitchen and tell him to add it to the list. I have a whiteboard on the fridge that is really handy.
With your DM, I suspect she was actually asking a question which was a conversation gambit.
In general, I agree with @PlanDeRaccordement's take on things here.
I don't think these people are being manipulative. It's very likely that they were brought up in homes where direct requests to parents would result in some sort of humiliation or where an extreme form of politeness was the norm and everyone danced around a topic instead of spitting it out.
There is an element of learned helplessness to it that is a concern, but you are not going to change that by being curt or snarky, either with an adult or with a child. Instead, try to empower the other person. With a child, you are probably contributing to the habit by presenting solutions every time or by being cross about requests, or in some other way disempowering him or her. Your task with a child who does this is to establish a solid level of trust that their need for validation and encouragement is going to be met, and you also need to address whatever anxiety they are feeling. 'Are you worried that you don't have any socks to wear?' or 'Don't worry, I'm sure we can find a clean pair while the rest are being washed'.
In general, you can use the phrase, 'How might we deal with this problem?' basically inviting the child to come up with their own solution, then offering praise for practical thinking. This should all happen in a context where the child is encouraged to make their own choices about many elements of their life - choice of two equally suitable outfits to go to the park, to a party, to church, and natural consequences for insisting on a t-shirt on a cold day. To a certain degree, you can offer a choice of breakfasts, lunchbox items, one or other veg or fruit at dinner time, flavour of yoghurt, type of cheese, etc.
'You can deal with that, right?' or 'I'm confident that you can figure out a good way to deal with that' are good for older children or teens. You need to set up systems in your home that ensure all information doesn't have to be funneled through you personally and verbally before you start on this. I'm talking whiteboards, family organiser apps, calendar sharing, etc. These empower the family members and take the mental burden off you.
With an adult, you are dealing with a more ingrained habit which often comes from their family of origin. Try to figure out if it's learned helplessness, which adds to your mental load, or extreme politeness/inability to make a direct request. You need to deal kindly and consistently with the learned helplessness because that isn't fair to the person shouldering the mental and physical burdens it causes, but the politeness could be reframed in your own mind as charm. Try to acknowledge the gentleness and appreciate it. For learned helplessness, again, get organised, and get in the habit of sitting your OH down to go over plans and logistics for your lives together on a weekly basis. Try not to resent 'yet another thing' you have to do - this is something that will benefit you directly. You know what the problem is and there is a way to turn things around, so don't just sit there fuming silently or responding with snippy remarks.
Be careful what you wish for here - having orders barked at you isn't at all nice. It's always a good thing to add to the level of kindness in a home. I would even go so far as to say 'Better kind than right.' Abrasiveness is corrosive to a relationship just as much as unfairness is.