I think payment holidays are required, rather than freezes which need to be paid back.
Can certainly be done with a mortgage. Just don't charge anything for x months, but extend the length of the mortgage so the full amount is repaid.
On the other side of the argument, I've certainly found myself spending considerably less during the last 2 months, as there is very little to spend money on (apart from utility bills, mortgage and the supermarket).
No football, cinema, pub, going out for a meal, shopping, gym, etc.. Nothing!
I think some of those savings may help people being paid 60% to 80% on furlough get by in the short term?