I would say no to the initial question about low credit lines they differ regardless of how you apply
as for applying all in one day or not--not sure that matters--kinda knowing which report they will pull kinda eases the pain of having all inquiries pulled from one report but it still depends some companies you really dont know who they will pull until its done
Capital one has a pre approval (sorta) on their website they pull all 3 scores to make a dec
Bank of america has a pre approval page on their website and also Spiegels
Good luck!!
Lots of post on here to generally find out what report is likely to be pulled