S!Elise and S!Tiki any good?

Ye unless you get perfect ivs...the most they are good for are their valor skills (and close def fodder for tiki).

Which....will pay off in the long run tho

Good for valor skills. Summer Elise can make a good blade tome mage too. Tiki is a bit iffy. She has nice physical bulk and Atk, but her low HP and Spd can be an issue.

I used Summer Tiki as my main axe wall until Brave Ike came along and she did very well at her job. I fear the powercreep has rendered her less useful but if nothing else, Close Defense and valor skills are rare.