There are many widths of tires for mountain bike tires just like road tires that will work and some without tread or very little tread - if you are riding on hte road, you do not need the tread. If you still want stability, just go with a tire that is almost as wide as the one you have, but has no tread. I've put treadless, really narrow tires on my mountain bike - almost looked like road bike tires, but they are a little dicey on the downhill - used to ride them on mt diablo uphill race in california.
I see you have bar ends on your bike - that for me is fine for hand positioning. I use those a lot but you will have to experiment if that is not good enough for you for hand positioning. What I've found is my commute is not long enough to bother my wrists or hands so I'm fine with bar ends.
There are lots of baskets, fenders, stuff out there to carry things. What I've found is that all mountain bikes are different and you have to look around for stuff that will actually fit your bike without like kicking your heel into them all the time, etc. I don't use my bike for grocery shopping except for smaller items, so I don't have all that pannier stuff. The easiest thing for me to carry stuff,clothes, shoes, etc. is a nice backpack. Also, I don't commute every day so I take extra clothes, etc. in my car on those days I don't commute.
I leave my bike lock at work most of the time so I don't have to carry that weight with me every day - unless, of course, I'm going to have to lock the bike somewhere else after or before work.
spoke