Hiya Lexi! No worries, that's what the forums are here for.
Pretty sure I have an answer for 4 of your 5 questions, still trying to figure out the trade cancellation:
BG:
1) Pretty much anytime you're having an issue with something happening automatically, it's probably 'Automaton'.

In fact, you may just want to disable it entirely, but for just the auto-res option, type "/rock", choose "Automaton", then "Rez", then uncheck the 'Enabled' checkbox.
2) If you want to still see Party frames while in a Raid, type "/rock", choose "Pitbull", then go to "Party --> Other"; make sure the checkbox for 'Hide party frames in raid' is unchecked.
General:
1) This one I don't see any options for, and I can't reproduce it (my 70 Mage seems to be able to Trade with level 1s without problems). Assuming you don't have any other AddOns not in the MookUI download, I'm still trying to figure this one out. If you disable 'Automaton' entirely and it goes away great, but I don't see any options in 'Automaton' regarding trades so I'm not sure that'll work.
2) Auto-decline of Guild charters is definitely 'Automaton' again - type "/rock", choose "Automaton", then "Loner", then uncheck the 'Enabled' checkbox.
3) This can definitely be done, as my Party Targets are smaller than my Party frames - in my case, on the "/rock" Pitbull menu, under "Party --> Other --> Size", the height is 80, the scale is 80%, the width is 225; under "Party Targets --> Other --> Size", the height is 60, the scale is 80%, the width is 180. The exact values will probably be different for you, but they can definitely be set to different sizes.
Let me know how things go - still trying to figure out the Trade issue. Is it only with Level 1s you have the problem, or is it just anyone lower than you?