Which audio interfaces do you recomment for that task?
I would recommend you to purchase Focusrite Saffire Pro 40 OR Focusrite Scarlett 18i20.
Also, additionally you can purchase Focusrite OcroPre MK II and connect it via ADAT to main audio card. You'll get 16 inputs instead of 8. That will be enough.
How many input channels do you prefer for drumrecording?
I prefer so many channels that allow to set up 1-2 mics per instrument.
For example, 8-mic configuration would look like this:
1 - kick
2 - floor tom
3 - middle tom
4 - high tom
5 - snare top
6 - Hi-hat
7 - overhead left
8 - overhead right
For this case kick and snare probably should be triggered. Kick shall be triggered to make it more flat and pump-in attack. Snare - to add sound of spring.
The 16-mic configuration:
1 - kick plastic
2 - kick port
3 - kick (subkick)
4 - floor tom
5 - middle tom
6 - high tom
7 - snare top
8 - snare bottom
9 - hi-hat
10 - ride
11-12 - additional overheads or yet another toms
13 - overhead left
14 - overhead right
15 - room left
16 - room right
For this case, if you have good instruments, nothing should be triggered.