Hi
KSDK 1.3 includes FreeRTOS, MQX, uCOSII and uCOSII options.
However I don't think that they will be suitable for the KL02 (with max. 4k RAM) since they tend to require a large amount of resources for operation.
If you require a sleak but comfortable solution (with co-operative scheduler) take a look at the uTasker project which includes KL02 support as a complete off-the-shelf project rather than a number of examples that you will otherwise need to piece together. It is suitable for the KL02 although the RAM limit will generally be something that you will need to monitor carefully (the project includes memory monitoring to aid).
Note that the KL02 and complete projects with it can be simulated in (approx.) real-time with the uTasker KL02 simulator which will greatly accelerate tight-schedule projects and allow best testing/code validations: http://www.utasker.com/kinetis/FRDM-KL02Z.html
Any work done on smallest parts, such as KL02, automatically operate on other KL, K, KV, KE, KEA parts when developed in the environment so there is no porting effort/investment needed when you move on to subsequent projects/products.
Regards
Mark