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Sinks are described as combinations of bowl + drainer. So 1 1/2 bowl + drainer might be what you want. Not sure if this link to search results will work for you.
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I reckon a freestanding slimline dishwasher is fine, if you can plumb it in with minimal effort. A more permanent kitchen in the future could use freestanding appliances rather than built-in, if it suits your tastes, or the freestanding dishwasher could be passed on to someone else. I use a slimline in a household of two and it's adequate (a full size would be far too big). So that seems like a less wasteful approach than buying new cheaper base units.
I wouldn't bother with the metod units as a temporary solution. They're supported at the back by a rail fixed to the wall. As a DIY effort in an old building (wall not flat and not perpendicular to the floor) I found it a pain. I solved it but you'd likely find it easier with an alternative that has "feet" both front and back.