Lunch time

yes, you can always use the extra bond.
Do you have apples? if you do it might be possible to get the rest of the prisms. There will be a lotto in the Christmas event, if you farm it enough you can get all the mana prisms.
During nero fest I farmed around 60 boxes and I got 5000 mana prisms just by burning all the trash I got from the friend points.

If you're planning to farm next event like crazy, there is a chance. However you should start grinding now - by farming Daily Quests (they're 1/2 AP cost atm).
If you run every single DQ at least once you should have 30 MP with use of 150 AP. Additional regenerated AP spend on 15/20 ember gathering [EXP cards], then burn all cards you've got (yes, even the 4star ones)
By doing that for whole week you should have 210 base MP + approx 100 (or more) MP from card burning.
Do not spend golden apples on this!
Next thing you need to do is to sacrifice your social life for a week and farm event currency (the socks that are used to lottery) like crazy. Lottery itself grants you Mana Prisms and Friend Points which are used to summon cards that you're also going to burn (both exp, servants and craft essences). Lottery also provides you a bunch of 3star exp cards that you also should burn into MP.
4000 MP in ~40 days is quite hard but possible.
If I were in your shoes I'd go for this method(s) BUT I wouldn't buy copies every time you get this 1000 MP.
Why?
There's possibility you won't be able to get this missing 4000 MP and you'll be left with 3/4 copies which imo are pretty useless. 2% isn't much and cost of the card (12 in party selection) is a lot. If you get a bunch of Mana Prisms just save them for something more useful like Mona Lisa.
Buy ChLt only when you get 5000 MP.

Hope it helps and my English isn't that bad

Honestly i myself don't find the appeal in Chaldea Lunchtime but if you are gonna get it, it should be MLB'ed cuz 2% isn't worth spending 1000 mana prisms