I would say the sentences you provided are very colloquial, which means in such a flexible language as Chinese, they are all valid.
Despite of it, there are indeed some reasons why people would come up with them.
动宾结构（verb-object construction）好动, though often used as an adj., consists of a verb+noun, and thus can play the role of predication and object. Many adj. are of such construction, e.g. 乐学/率性/恋旧/怀春…
“是” is wordy, and are often omitted in conversation (and informal writings).(But such omitting sometimes convey other tones: 你谁啊？(contempt, sarcasm)).
adjectives are treated as verbs extensively.
Sentences are broke by topic change instead of grammar requirements.
Here I write a brief passage including 啊lot of depiction to illustrate it further. And I will insert spaces to help reading.
我的 邻居 张军 沉默寡言，喜怒 不 形 于 色，日 不 出户，足 不 下楼，旁人 难 窥知 其 生活 一二。年关 将 至，是夜 雪 骤 风 紧。我 上楼 时 瞥见 他 家 透出的 灯光 依然 晦暗，平日 习以为常，而 在 这 凛冬 万家灯火 之时，不由 少 发 怜悯。家里 最近 包了 饺子，我 想着 送过去 一些，正好 也 看看 他 的 生活 如何。
左手里 盛饺子的 碗 还 火烫，门 却 半天 也 不开。正当 我 放下 敲门的 右手 要 分担 那 苦差 时，嘎 的 一声，一头宽 的 门缝 间，是 张军 背光 的 人影。我 看清 了：促狭 的 房间 靠墙 贴着 一铺 床，衣物 和 被褥 随意 交 裹 着，隔着 角落的 木衣柜，蒙着 报纸 的 窗户 下，是 一方 书桌，窄小 而 拥挤，叠着、立着，似乎 都是 书，一盏 台灯 却 从中 探出来，明晃晃 照着 几 页 纸，密密麻麻 都是 字——只能 看见 这些 了。
“什么事？”他 合了合 门。“送 点 饺子。”我 有些 局促。“那 多谢 了。”
……相顾 无语，我 只得 转身，然后 楼道 的 残晕 倏 地 消失 了。
Note that a sentence is long and within it the grammar subject seamlessly changes. Adjectives function as predication plus predicative. Inversion is quite common in depiction and sometimes the subject is even omitted. Prepositive and postpositive attributives are balanced. Here and there 是 is replaced by other figurative verbs.
In short, you can freely use all these techiniques to elaborate your writings. You don't have to be that accurate.
