Learn English – What comes after “can”

Your "Even to Julia" idea would work in the right context, e.g. even Julia, who hasn't worn a dress since 2012 when she was invited to be a bridesmaid at her cousin's wedding, found the prom dress to be the most important part of the whole affair.

There is an implicit comparison when you use "even".

You could gain more naturalness and confidence in your use of "even" by looking at example sentences in dictionaries.

I find both can and will be able to possible in all three cases. The difference (as is usually the case for decisions on tense and aspect in English) is not in the objective events, but in how the speaker is choosing to view the temporal relations. If the speaker chooses will be able to they are making the implication explicit that something will have changed by the time it comes around; but that is their choice, not a requirement on them.

I find the case for will be able to weakest for no. 8: certainly possible, but not what would occur to me.

In the case of no 10, will be able to is implying not that we can fit it in some time between now and next week, but that things will be different for us next week, so we will have time to do it.

Similarly, in No 11, will be able to is emphasising that something is going to change between now and Saturday that will give me the ability to pay; but can is still fine, just less specific.

[Native British English speaker].