Absolutely. You can use Excel to add the new columns, you just need to make sure that you save in the proper DBF (DBASE IV) format, otherwise the database will be corrupted and result in codebase errors.
In terms of appearance.dbf, you'll also need to fix the shoes, as the IDs are different. Dunk packages are another thing you'll need to look out for, as there are a few differences and DUNKPACK is also closely tied to certain Freestyle Superstars movesets in NBA Live 06.
The only files that you need to copy across are players.dbf, appearance.dbf, teams.dbf, and coaches.dbf. You could copy teamgear.dbf, but there might be some missing jerseys. You shouldn't have to do anything with teams.dbf or coaches.dbf, perhaps aside from an errant value here and there. You'll probably also need to make some manual changes to location.dbf.