didn't answer this first time it came up so i'll have a go now!

Dummy - apart from a teeny newborn or an immunocompromised bubba, i figure it's not too bad. yes, people may not have washed their hands in the last few minutes, but really, as a society, we are TOO sterile and obsessive about things and it's too our detriment. our immune systems NEED to be exposed to small amounts of germs to be able to build up a decent efence for when it's under attack by something big!
Food - really depends on the food. i am not averse to saying no if it is something that i don't agree with (at 14 months she doesn't need lollypops!) or food that is not appropriate for the time of day (we have friends that think chocolate cake at 9am is a good idea - i don't really agree lol). Maybe i have an "air" about me - no one will argue! but having said that, i don't mind her having some treats, so when i DO say no, people know it's not just me being pedantic... i have been known to make an alternative suggestion "ooh, it's a bit early for chocolate cake, how about you get you a rice cracker/sandwhich/piece of fruit" or something like that. i have found that people respond better if you're not "denying" something completely.
Teasing - i dunno - i guess it depends on the context of it. i was teased mercilessly as a kid and i never took it personally because my parents used to use the common teasing things as terms of affection for me. so i guess i'm ok with it (don't shoot me - it's my personal opinion!) - we tell DD she is our sweet little 'ranga and a little fatty pumbaa. it is said with affection. i don't have that much of an issue with it
Older children touching the bub - i agree with Onyx. i have no issue, as long as it's safe. i also don't mind DD having cuddles with kids that are a bit unwell (cold etc) - it helps build her immune system!
Disciplining my children - provided it is not done with violence or fear as motivation. If E is doing something wrong and i don't see it or someone else is in a better place to speak to her, i would hope they'd do it. i don't agree with intimidating children though (so i DO have a big issue with my dad disciplining her cos he uses his size and volume to scare her). i am more than happy for someone to say "no E, that's not right" and to distract her or negotiate with her. Rumpled Elf - what you're talking about is what i agree with. it doesn't seem like discipline, more guidance and encouragement to do the right thing!