On the needles it's hard to tell from the pic what you have,if you took it from the pointed end it would help,but on the needles the rounded point ones are used in vinyl & cloth,the leather points will have like a knife edge on them(they won't be round)they make a better looking stitch in leather.
The bobbincase is broken & not for this machine.
The feet one has finer teeth than the other so it won't leave has deep of marks on top of the leather.
Last yes,the bobbins are small that's why these machines are used for repair work where you don't have long runs of sewing & the best thing to do is use the smallest thread you can to go further.
Bob