Absolutely you can mix and match 1st / 2nd stages as long as you set the intermediate pressure to what the 2nd stage wants.
That said if you already have a set you can just get it swapped over from yoke > DIN.
https://www.amazon.com/Scubapro-Din-Conversion-Kit-Universal/dp/B0000DYVG3
Or you could save money and get this https://www.amazon.com/dp/B0000DYVG3/ref=cm_sw_r_cp_apa_glt_fabc_7RS1K7MJP5JTAJKVVJMX?_encoding=UTF8&psc=1
The body of the DIN and yoke first stages are essentially the same. The only difference being section that attaches to the tank. For what you are wanting to do it is probably easier to buy a yoke first stage and then get the corresponding DIN conversion kit. That way you will have all the parts for both.
For some reason the manufacturers seem to expect you to switch from yoke to DIN and not the other way so there only seem to be DIN kits. Just make sure there is a kit available for the first stage you choose.
It is a pretty straight forward swap out with some basic tools but if you aren't comfortable doing it yourself any LDS that does servicing should be able to help.
Example: