It's me again - I'm so sorry I keep asking questions

I was just wondering... my plan for my 5.5 gallon tank is to get 2 otos first, acclimatise them, and then get me a betta female. I've learnt from here that it's best to get otos before the betta? I'm going away for three weeks in about 3 weeks.. and knowing how delicate otos are, particularly in the first month, what kind of holiday care would you advise for them? My friends and relatives aren't as.. fish-loving as I am, so I don't think they'll be particularly supportive with the water changes and testing the water - they'll feed it, but they won't be traipsing to my place everyday to feed it vegies and take it out after a day. I'm considering waiting till next year after I get back from holidays before I get my otos, but I'm wondering what you guys do with your little otos when you're away?
P/s: The tank is cycled from previous fish.
Also - one quick question about feeding them vegies. I tried feeding a slice of zucchini to my previous fish once, and i left it in there for 12 hours, none of them tried it. Then when I took it out, it was rock hard - do you guys prepare/blanch/nuke/cook your cucumbers/zucchini before you put them in for the little ones?