Photography seems to be considered one of the harder skills to supermax - it's always been a little buggy. I think it would be much easier to supermax if you're able to travel freely (especially the challenge where you're photographing unknown sims), but there will still be some photo subjects that don't register properly (e.g. if you have Late Night, the Nectary in France always seems to register as "Hotspot" instead of "Nectary", and combined rabbit holes sometimes only register as one of the parts).
I agree that charisma is very easy - if you buy the Observant LTR, it'll get your required traits in a hurry, and also make it that much more likely that you'll get interactions with people that will give you 2 +'s for the relationship bar. Introduce yourself to everyone until you complete the Celebrity challenge - don't worry about doing more than that. Once you've got that done, use Charming Introductions to add to the boost you get when you introduce yourself to people, and Ask About Career which might open up more "double plus" interactions - it shouldn't take more than one or two interactions to get the next few sims you meet to Friend, and you can use jokes for those. Buy the Never Dull LTR, and you can use the "double plus" interactions repeatedly to make best friends fairly quickly. (Also, don't waste time talking to known Grumpy or Mean-Spirited people...)