Hi Sasha, first of all congrats on your pregnancy.
IMHO if your friend has to care for a 2mo newborn, it would be hard for her to be your support person. But you can always ask, who knows someone else can take care of bub for a while.
During labour, DH was my support person. Mum was there as well, but it was DH who literally stood there beside me all the time. There were 2 midwives helping out, plus my OB. So the birthing room was pretty crowded LOL
I know it is nice to have lots of people dear to you supporting and helping out, but I guess when you are in so much pain, you might not be able to interact with lots of people anyway. Thats said, my labour was a pretty quick one, arrived hossy at 10am and deliver at 12noon. So things might be pretty different with a long labour.
HTH and good luck with the rest of the pregnancy