I would like to know how to control the other parameters like envelopes over midi. They are in sysex format.
Controlling envelope parameters can differ depending on the reface engine. A reface CS, for example, like an analog synth, all oscillators go through a single ADSR so setting the envelope is simple and can be handled by regular cc (Control Change) messages.
On a reface DX, for example, each oscillator (called an Operator) includes its own Amplitude Envelope Generator, and therefore is more complicated to adjust. Yes, the four Rate and four Level parameters that control the AEG of an Operator are accessible via Parameter Change messages.
A reface DX "Parameter Change" message template is shown on page 6 of the Data List booklet:
F0 43 10 7F 1C 05 hh mm ll dd F7
The High/Mid/Low parameter values for the Rates and Levels are shown on page 9
dd is the Data Byte 0-127