To reverse a loop you need to store it in a table and read it with [tabread~] (or [tabread4~]). This way, if you send a negative frequency to [phasor~] (which will be driving [tabread~]) you'll get a backwards reading.
The same applies for tempo, note though that the pitch will change as well. If you want to play a recording in a different tempo but the original pitch you'll either need to play it back faster or slower and shift the pitch down or up (check [soundtoutch~] by Katja Vetter for this implementation) or use the phase vocoder (Help browser -> Pure Data -> 3.audio.examples -> I07.phase.vocoder.pd).
As for your last request, you should probably send the 6 loops into one [writesf~] but make sure you scale them by multiplying them with 0.166666 (which is 1/6, it's better to multiply by the inverse rather than divide, divisions are more CPU intensive).