Definitely sounds like a good DIY set of projects, assuming the concrete block is not falling apart en masse, just a few local breakouts.
I would guess that is not salt coming in, probably efflorescence like this - google this search phrase for pictures - images of efflorescence -
which is lime leaching from the mortar migrating in with water, then evaporating at the surface, leaving behind the lime. Meaning you have a leak at least at times, but it is evaporating as fast as it comes in.
If this is concrete block, salt would not cause holes in the foundation - probably low quality spots in the block that are just breaking up with age, assuming you have only a few of them. I would get a good crack repair caulk for small cracks (Dap or M-D or Dow, called Concrete Caulk, gray, comes in caulk tubes for ease of application). For larger cracks and the holes in the wall, assuming the block is not totally falling apart, I would get a good hydraulic grout - waffle or cake batter consistency to trowel into the cracks, thick bread dough consistency for packing into the block wall holes.
Be sure to clean out cracks first - scrape out broken/loose pieces, then hose or airblast out if feasible - even a leaf blower is decent in many cases if you can't use hose without making a mess and don't have an air compressor. For the block wall, take a chisel and small hammer and break out and clean out the broken or deteriorated material that comes out readily (without whaling on the block), and gouge and wash out any dirt coming into the hole from outside - without burrowing out a big sinkhole outside, of course. If dirt keeps coming in, clear out the block area so there is a little hole in the dirt on the other side of the wall (if you can't dig down to access both sides, which would be better) and then stuff a plastic bag in there to block the outside of the hole so the dirt can't come in any more, then wash out the block so the grout will stick. If you expose the holes cast into the block, you will probably have to stuff a plastic bag down in each hole too so you don't fill the wall with grout - go 4 inches or so down with the bag to leave room for some grout. Then grout it up - the larger hole may take a couple of passes if it tries to ooze out of the hole - or you can block the bottom part of the hole off with several layers of duct tape for 6 hours or so till it sets in place.
IF you can work from both sides so much the better - do inside first with a plug with smooth interior finish (and filling unplugged portion of block voids), then after that sets a day or more, come in from the outside (where you don't care about appearance as much) and pack the voids full of grout - can use duct tape to seal it in and just bury with dirt imemdiately.