It's taking Kendra forever to sign consistently. She does "more please", "chicken" (I taught her that one!), "all done", "thank you" and "want" but "more" is done the most, and like Thomas we have to bribe, force, or coerce! She's speaking some words with the signs now, though. Then every once in awhile she'll say a brand new word, correctly and in the right context, then never repeat it again. Little Stinker!
I love doing the same things the therapists do with Kendra too, and just like you I get excited when the reaction I get is the same one Cindy, Andrea or Lisa get. When Katie was first diagnosed with Autism, I'd write down the things the therapists got reactions to and then buy two of them - one for Jenny's house and one for mine. That way the input Katie got was identical from all of us. She stayed with us when Mom and Dad were working so I had more free time to work with her. Jenny just got hired as the assistant cook at the school here, so I'll have Kendra while she works, so we'll get back into that routine again because it was so helpful to Katie.
Any way to mend that crack in Thomas' hearing aid? You are absolutely right that he needs to keep them in, if for no other reason than to allow them to become part of his everyday routine. Good Mommy!! Those are two really sweet, adorable little ones! Cute picture of them!
Thomas does the same darn thing! Says a brand new word, appropriately, and then never again. He's said waffle once, and cereal the other day. He said "bae" and I said "baby?" and he started clapping. They are stinkers

The hearing aid thing is hard, he screams bloody murder when I put them in. Breaks my heart. I fear mommy often gives in.