G'day,
Dishwasher - Width should be ok, you need 605mm. Check the height you have, will it go under the bench?
Oven - Check the installation instructions online before purchase, some need more ventilation than others. With the height, it's easy enough to build a frame or box to sit it on and then you could just paint a piece of MDF to match your door colour for the face.
Hotplate - One option is to get a stainless steel frame made up with the correct cutout for the new hotplate and big enough to cover the old hole.
Just a bit of mucking around but can be done.
Good luck.