1. I don't think your two-week trip is any problem. You are proving you're a couple who share a home, not that you never take an individual trip!
2. I'm sure you've seen posts from me saying this before -
it takes as long as it takes. The INZ office you have to submit to will have a processing times page you can find by Googling, which will give you a guess based on recent averages, but it's never a promise. Of course, you KNOW they know you, and that you have a partnership they have accepted as genuine, and this is a very good sign, but still...
3. INZ officials are entitled to conduct interviews with anyone on any subject if they feel it will improve their knowledge of the facts of the case. If anyone gets called for an interview about partnership it's because the officials are responsible for checking that the partnership is genuine, so in general, they will be making sure that the two people give roughly the same answers to things like how long they have known each other, how they met, etc., and they might ask about the other partner's background and family. These things are not difficult for genuine partners, but will catch out anyone who is faking a partnership just for one of them to get a visa.
Some of these interviews go into small matters like who does what domestic chores, how does it work, entertaining v. cooking, if you have people round for a meal, when in the day does the other one brush their teeth - again, real partners won't have any trouble, but fakers would be caught out.
HOWEVER, in your situation, with two partner-sponsored work visas behind you, I very much doubt you'll be called for interview. Basically, they've already shown that they accept your partnership exists, and all you're having to do now is bring the evidence right up to date to show that you're still there, still together.