Hey @llama
Waves emulates the compressor section of the API channel strip with the API 2500 Bus Compressor, separately they also emulate the 500 series EQs. ( EQ Also emulated by IK Multimedia and Overloud BTW ), but in this case, you're more after the compressor, the goal to use the UAD API channel strip was to glue and give compression & analog saturation to the mix. Another alternative could be to use something like OMEGA A from Kush Audio.
Next to UAD, the other very good one ( and complete ) API Channel Strip IMO would be Softube American Class A, it's the first Console 1 channel strip emulation that does not requires users to own Softube Console 1, it will work as a native plugin.
Slate Digital and the Everything Bundle offers also some API modules to work with.
That said, you do not have to use specific API to achieve the goal explained in the tutorial, the importance here is to glue, compress & saturate the all mix, which can be done with any channel strip and fine adjustments, but of course you won't have the exact same coloration & sound by the end, it's a matter of taste I think.
Hope that could help 
Cheers !