Help with a super picky 6yo in a new environment!

My partner and I have custody of his 6 year old son every other week. We have been together over a year now, and are planning on moving in together next month. His son and I get along really well, he’s quite attached to me.Anyways, SS is an insanely picky eater. He will eat peanut butter sandwiches (white bread only), noodles with butter (just butter, and only certain kinds of noodles), apples (only if they’re crisp), cucumbers, waffles (plain), Cheerios, and milk. That’s pretty much it. He used to eat a few other things, but without rhyme or reason has completely refused previously preferred foods over the last couple months. It’s getting worse and worse - last week there was ONE SPEC of black pepper in his noodles, and so he cried and completely refused to eat them. We’ve taken him to restaurants, let him choose what he wants - but when it comes, he refuses it and pouts the whole time.We’ve tried letting him just refuse meals and go hungry - but he’s gone two days without a single bite, and would have kept going, too. We’ve tried letting him grocery shop with us, but he just wants the usual foods. Suggesting other foods makes him whine and cry.The biggest problems are that we can’t get him to eat out anywhere (restaurants, friends/families houses, etc) without a fight, but also that he’s actually getting MORE picky as he gets older, and I’m worried he’s going to run out of options for food.Since we will be moving next month, we’ve agreed that it’s time to try to address this. We want to give him some time to adjust to a new house first, but we are hoping to give him a heads up about what sort of rules are going to change.So my question is: HOW DO WE GO ABOUT THIS?! What’s worked for those of you with picky children?? I’ve done so much reading lately, and there’s so many different ideas from people. I need some suggestions! Starting right from how firm to be (do you let your kid refuse their meals? Give options? Make them wait before giving them preferred foods?) and how to slowly start introducing food (dinners are going to be served as a family at the table with no TV/music, no exceptions). Any suggestions for food to try?? Send help!! TIA via /r/Parenting https://ift.tt/2GUks1n