On my phone not laptop today so I will be brief(er)!!
To everything above & the consensus of GO especially while they are little & will love DLR, I agree 1000%.
There’s a great thread here about a lot of your questions. The link above is my specific response & includes (scroll down to where the bold text starts) a comparison of DLR & WDW rides, all with little kids in kind as the whole thread is about taking kids to DLR.
Any other specific questions, ask away!!!