You can use both. The BJ57 is better than insulation, no seams for water to get through, and has a rubber consistency. You would put it on the outside. I used it on my original chicken coop floor in 2013 (now a tool shed). It's still in pretty good condition considering it is being walked on now. Insulation would be applied outside after the BJ57 to help to not lose heat through the concrete. You don't necessarily need the BJ57 if you use foam board, but the BJ57 offers no insulation.
Ceiling fans would help keep the heat lower in the winter. Reverse them in the summer (if possible), and if you have a roof vent or vents, pulling up the hot air will help vent it through the roof vents. A lower intake vent could help that process by creating a chimney effect. Two fans in the opposite directions (2 doors?) would be helpful, too. I would try it and see - if you are trying to save money on more professional equipment or want to wait and figure which higher end units you will eventually want to use. I can tell you from my first, smaller greenhouse, portable fans and/or non-greenhouse specific fans means extension cords and less fan life since the average fan is not meant to function in high humidity like a greenhouse. They won't last as long. My experience is 1 year from a cheap fan, 2 years from a better fan, but many years from a fan designed for a greenhouse. My first real greenhouse circulation fan is 4-5 years old and still going strong.
I have to tell you, I know a lot about greenhouses, but no first-hand experience with GAHT (ground to air heat exchange) systems or heat pumps that some use...just what I read and watch. If memory serves me, the ideal depth for a GAHT system is 1 layer of pipes about 6 feet down and another set about 4 feet down. I don't think I gave you this link or you may have already stumbled upon it on your own.
https://ceresgs.com/gaht-syste...
Here's another one about two ways to insulate. I may still do the Swedish Skirt insulation since it can be added after the greenhouse is built.
https://ceresgs.com/solar-gree...
The tendency I think when building your first greenhouse is to overthink it and thinking you can make it perfect the first time around. It's like building a house when you have never lived in one. Greenhouse growing requires a rather sharp learning curve. You and your new greenhouse will develop together as time goes by. Do your best, but you will see things you could have done differently, or might change like me, once you are actually growing in it for a year or two. Eight years and I am still learning everyday in my greenhouse. Most important thing is have fun!
