My plan is to do the BRRRR strategy.Any way, one of my biggest concerns is getting the financing, I have saved about 10k of start up money and I'm hoping to do a FHA loan for the first house.

Downside is that you will have a higher payment but probably better terms for interest and timeline.You may be able to find an equity loan that will take a second lien position with the seller financing still in place if you have enough equity in the property. 

The biggest challenge was getting the tenant out.

The 2 biggest considerations we see investors face (in my narrowly defined bubble) are #'s 3 & 4 that Dave listed above

Far too many simply believe their biggest issue will be finding the money to invest.

Is there any downside to this ?

I highly suggest using BP - lots of podcasts, great forums, etc. here - a great place to get ideas and questions answered.I also suggest checking out the local investment clubs - the biggest two are Pittsburgh REIA and ACRE.

Perhaps others with lease-option experience can comment, but only downside I see is the lease option itself, as opposed to a purchase (flushing $3500 down the drain monthly). 

I am going through some analysis-paralysis and second-guessing myself, as this will be one of the biggest financial decisions my husband and I will be making - aside from buying our primary residence - which I wish we could do all over again with what I now know.

The ONLY downside in my mind might be the street appeal and parking.