Gee, Nifft... I think your numbering may be just a little bit off! 
You numbered them 1-16, but I count at least 41 different critters there. More if you're going to have multiple elemental and/or dragon sizes.
Of course, Morpheus also list "Animals (Apes, Bears, etc.)" as a single entry - I believe that's already about 60 individual critters, not counting dire versions. Ditto with "Giant Vermin (Rats, Spiders, etc.)" - that's about 30 critters.
Trust me, it gets a *lot* harder if you try to narrow it down to just 25 individual monsters. Would you rather throw out black bears or ghouls? The grey ooze or the giant bee? The ankheg or the harpy? If you had to narrow it down to just 3 animals and 2 abberrations, which ones would you consider essential?

You numbered them 1-16, but I count at least 41 different critters there. More if you're going to have multiple elemental and/or dragon sizes.
Of course, Morpheus also list "Animals (Apes, Bears, etc.)" as a single entry - I believe that's already about 60 individual critters, not counting dire versions. Ditto with "Giant Vermin (Rats, Spiders, etc.)" - that's about 30 critters.
Trust me, it gets a *lot* harder if you try to narrow it down to just 25 individual monsters. Would you rather throw out black bears or ghouls? The grey ooze or the giant bee? The ankheg or the harpy? If you had to narrow it down to just 3 animals and 2 abberrations, which ones would you consider essential?