I am in a similar situation. Im taking 5 AP classes this yr (Sr. Yr), which is the most my school allows to be taken in any year. Out of those 5, I have an A+ in 3, an A- in one, and then a B- in AP Lit. I asked my guidance counselor if this would hurt my chances in RD applications and, without even asking me for my other grades, she said no. Apparently, adcomms would rather see you challenging yourself in a difficult class rather than taking the easy way out and dropping it or not taking it in the first place.