Basically a repeater is a receiver, transmitter, power supply, and a controller. If you look inside a Yaesu DR-1X repeater, it has two mobile radios along with a power supply and controller. So yes, two mobiles will work in theory. How well it works depends on several factors--mostly, what radios you use. There are many amateur repeaters that use two Motorola Maxtrac radios. The transmit radios require a minor modification to the output RF power circuits. I've built several and know of several that have been in use for 10 years--using one on 2m right now. Mobile radios are also used to link repeaters together. There are lots of bells and whistles that radio clubs add to their repeaters...they all cost money and really have zero effect on RF performance--do you really need a $500 controller with voice ID vs a $90 CW model? Not for what you need. Your country's laws have to be taken into account--we don't know them.
Don't skimp on the feedline! No LMR-400--hardline/heliax if you can. The feedline can't have foil inside. ID-O-Matic, NHRC, and Elektra controllers are cheap and accomplish the job--that is if you country requires a repeater to ID--if not you may be able to direct wire them together. You HAVE to add an extra fan on the transmit radio because you are using beyond its duty cycle and it will fry without extra cooling (not a tiny fan, something that puts out as much air as a blow dryer). Fiberglass antennas are not made for repeater use...people do use them and you can, just factor in replacing it after a couple of years. The wind will bend them and over time cause micro-cracks internally. This is fine for simplex use, but in a repeater it will cause crackling in the signal. Proper repeater antennas are very expensive in comparison, thus you can use fiberglass over and over for many years before reaching the price of a DB antenna.
These two websites may be helpful:
The Repeater Builder's Technical Information Page[emoji769]
Batwing Laboratories