Rogaine - 1 month in. If I were to stop Rogaine altogether, will I get back the hair that originally shedded?

Hairs do not usually grow back after stopping a medication (Rogaine) that was intended to grow hair.  Anything is possible.  Internet may be a good resource for general information but it may also be a source of confusion and misinformation.  

Some initial shedding can be expected and this should improve as you continue to use the minoxidil.  Generally speaking, minoxidil will only recruit new hair growth while you are using it, so a return to base line is expected if you stop it.  Cellular therapy such as PRP can cause improvements similar to minoxidil or superior and last longer with the added benefit of slowing hair loss.  I usually recommend a combination of all therapies for the best non surgical approach. 

As you've pointed out, shedding is common with minoxidil (Rogaine) in the first 1-2 months. Will you get the hair back if you stop?It's not possible to say definitively yes or no. But those on finasteride are "more likely" to have a short term shed and resumption of density than those not on finasteride. If you have ongoing concerns, be sure to have a hair specialist review all your details.