Youll need to do directory renaming if you want the bots to work though.
Basically the bots will work normally if the directory is named "esf" any other name and it will mess up. So if you have 1.2.3 installed, youll have to switch between the 2 by renaming the directory.
The model issues are there due to the same reason probably. The game was trying to prechache the files needed by 1.2.3 so models and sprites were missing, and it also explains the meleesounds.sc thing, since thats an exclusive error to 1.2 as its linked to advanced melee.
Now what you do is this.
1.) rename your existing ESF 1.2.3 dirrectory to something else like "esf12" and the "esf_addon" directory to "esf12_addon"
2.) Install esf 1.1 so that you get a directory named "esf" in your half life directory.
3.) Install the steam fix and the bots
4.) place the fmod.dll in to your half life directory
5.) Restert STEAM and you should see esf v1.1 in your games list, so rightclick on it and go to properties.
6.) Cliick on launch options and add "-noforcemspd -noforcemaccel -noforcemparms -nojoy -nofbo" in to the window that opens.
7.) Once in the game make sure to dissable the "HD models" option in the video settings.
Start the game and have fun. In the key configuration there are 3 extra commands for the mot menus, so use them. Also boty by default dont seem to melee very much, so make sure you use the bot menus to set their melee %
Now 1.1 is a totally different beast than 1.2, so be sure to go though the flash manual included with the install as there are such things as locking on in order to swoop, and so on. I guess itll take time to get used to, but the pro scene back in the day could bounce you round like a pingpoing ball. You will see what skill that was once you get ingame and try a simple double hit XD
If you want to switch back to 1.2, then rename the "esf" directory to "esf11" and the "esf12" directory to "esf" along with naming the "esf12_addon" dir back to "esf_addon". Do this in reverse if you want to switch back to 1.1
Hope this helps. Also limit your server slots. For some reason the server seems to be set to 28 people and if you make the bots fill the server it lags up badly. So put it down to 12 or so.