last minute lunchtime

I....don’t think Chaldea Lunchtime stacks like that though.

Chaldea Lunchtime will return in the shop for 1 rare prism if you have one readily available just purchase it and the expiration date will last over a year that should give you plenty enough time to save up on Mana prisms. In the JP they do have Chaldea tea time but that is only a 5% bond boost if not used on friend support (but if you grab a servant from friend support holding this it will grant 15% total bond points).

1 MLB Chaldea lunchtime and 2 MLB tea time (the one you own and one from support) will give a 30% bonus in bond points

Mona Lisa in the rare prism shop, but once unlocked it won't have time limit to purchase them. So you can get another lunchtime and get 4% if not combined and equipped separately, or just save up your prisms and unlock it next fall from the rare shop.