hi,
Michael: I would also use diodes that are specified at very low forward voltage drop.
Maybe should it be an AND5 gate instead? It may be constructed from either 7421 or 7411A or even 7408 (=
With 7421 (two AND4) and two interrupt pins (here: INT0 and INT1) it is possible to control upto 8 buttons.
The reason to use the IC is that it produces defined V_IL and it is more easy and cheaper to obtain IC than such diodes with very low forward voltage drop. SMD is welcomed to decrease board size.

Regards,
Oleg