The intake manifold is how the air and fuel get into the engine. Between it
and then engine block is a gasket the stops coolant from leaking out. If
that gasket wears out you will end up with a coolant leak, either outside
the engine or worse into the oil. If it was leaking inside I would expect
you to see foamy oil under the filler cap.

Wheel cylinder is part of the brakes. They're found in drum brakes, so that
would be the right rear wheel unless your car is 30+ years old. A little
seepage is normal around the rubber seals. If they show you the brakes and
pull the rubber parts back and say "See! A leak!" they ARE trying to rip you
off.

The oil pan gasket it just what keeps the oil from leaking out around your
oil pan. Do you end up with oil spots in your driveway under the engine? If
not I wouldn't worry too much about it.

Front crank seal is what stops the oil from getting out of then engine
around that pulley wheel at the bottom of the engine. Again, do you have
lots of oil leaking onto the ground or spraying the parts under the engine
compartment? If not, I wouldn't worry too much.

You didn't say what year or model car, so no idea how difficult any of these
jobs are. The only serious issue is the manifold leak. The brakes could be
serious too, but if you don't have the brake light coming on and the brakes
feel fine you probably don't need to worry.

...Now, I'll just bite my tongue about the screw job.

Get a second opinion from a different shop.  Those items may be bad,
or they may be trying to run up a bill on you.

Some of those items, if really bad, could make the car dangerous and
undependable to drive, so I would have it checked sooner than later.

The oil pan gasket is a gasket between the bottom of the engine block
and the "pan" (stamped steel piece, actually) that keeps the oil in the
engine. The gasket is NOT pressurized, so any leak is probably more like
a "seep." Its a fairly major task to repair the gasket, so I'd probably
just ignore this one. Does it leave big oily spots in the driveway? Do
you have to add oil often? If not, don't worry.

The front crank seal keeps oil from leaking out past the crankshaft at
the front of the engine. Again, some "weeping" is normal, and if you're
not leaving big oily spots where you park, don't worry too much or wait
until you can afford it.

The right wheel cylinder is part of the braking system. You don't say if
its front (disk brake) or rear (drum brake?). BTW- it would be helpful
to know what kind of car this is!!!!  At any rate, drum brake wheel
cylinders often weep a little fluid and that's normal, but if they drip
enough to show on the back of the wheel or to get the lining wet, then
its very important that this be fixed.

The lower intake gasket leaking coolant is VERY important, because it
can lead to engine failure, oil mixing with water, all sorts of bad
things. Again, it would REALLY help to know what engine this is. Several
manufacturers have had intake leak problems and some of them have
offered extended warranty coverage, so you might not have to pay for all
of this repair if the car is covered.