Im not sure on the scar opening or the chance of miscarrying.

But from experiance i can say (in my case...yours could be different) but i was pregnant within 4 weeks of DD1 birth and my uterus was fine as was my body, and i didnt think it was to soon.

I found it easier falling pg so soon rather then waiting.

You ave kids when your ready. Perhaps speak to your GP about TTC #7.