I’ve done a test cycling to and from work over the last few months. With and without hi-vis, pannier, helmet, etc.
I found that the hi-vis does seem to help, with less cars pulling out on me (still happens though), but makes sod all difference to anything else.
Panniers on the back, cars give you more room for sure.
Helmet…I’ve found cars less likely to wait, and give me less room, and cut in sooner, when I’m wearing one.
My tip – fit panniers (even if you just fill them with balloons!).
8)
Oh, as for the kids thing, dunno, don’t have kids and don’t care what others do with theres. Actually, might be worth borrowing one for the rack though, and seeing if I get more room than I do with panniers…