All three are ordinary, and only one of them is really a fee. Worth saying that the exact names and rules vary a lot by country and even by region, so treat this as the shape of it rather than the letter of it.
Origination charge is the lender being paid to make the loan. It is a fee, it is theirs, and it is the one that is genuinely negotiable or at least comparable between lenders. Some lenders bury the same money in a slightly higher rate instead, which is why comparing this number alone will mislead you.
Prepaid interest is not a fee at all. Interest is usually collected in arrears, so on completion day they collect the interest for the days between closing and the start of the first full period. You are paying for days you actually have the money.
The escrow or impound reserve is also not a fee. It is your own money, parked with the servicer so they can pay your property tax and insurance when those fall due, plus a cushion of a couple of months. You get it back or it gets used on your behalf.
Ask for the itemised sheet and sort the lines into lender fees, third party services, and prepaid or escrowed money. Then push only on the first group. Arguing about the third group just makes you look like you have not read it.