Yes, the XE-7 with the electronic controlled shutter is nice. Yes, it is also quiet. A nice camera.
The MC ROKKOR 1:1.4 f=50mm is a good lens. It will focus down to just under 18 inches, but you might like the results better if you get a reversing ring and turn it around, especially if you want to go closer. For more serious macro work, look at the MC MACRO ROKKOR 1:3.5 f=50mm lens. That one will down to about 9 inches and a full 1:1. If you need to go closer, look at the AUTO BELLOWS ROKKOR 1:4 f=100mm bellows lens.
No, the mirror does not go into a Mirror Lock Up mode if you set the self timer. I do not think that any of the Minolta cameras from the XE series and onward had an MLU. They did bring it back on a couple of models of the AF cameras. If you need that feature, go back to the SR-T series or the SR-7. Many of them, but not all even in the same model designation, had the rotating MLU control on the side of the lens mount just below the shutter speed dial. The SR-T 102 is one model where it may or it may not have the MLU. Look at the camera lens mount on the side.
One point of the XE-7 are the batteries. The camera does require batteries to work. There are two (2) and you will run them down if you leave the camera on when putting it away. Turn the camera OFF when it is not being used, and you will enjoy normal camera battery life.
Minolta considered that the shutter and mirror braking mechanism was so vibration free that mirror lock was unnecesasery .