成程！I think you are referring to ‘だ’, which is ‘contained’ in the い-adjectives (赤 ‘red’, 赤い ‘is-red’ as per CD) but both nouns and な-adjectives need ‘だ’ to ‘exist’ (花 ‘flower’, 花だ ‘is-flower’, again as per CD).
On its part, ‘が’ is a particle that marks the ‘subject’ and no other particle has this particular function, so it can not be ‘masked’. It may be omitted, which is not unusual in Japanese (those zero pronouns so dear to Jay Rubin), when it is clear from context.
十分なお金さえあれば、日本に住めたかも。
If only I had enough money, I could have lived in Japan.
Yes! I didn’t realize I misspoke and said が when I was referring instead to だ in this case. Thank you for being patient with me as we cleared that up.
You said
both nouns and な-adjectives need ‘だ ’ to ‘exist’ (花 ‘flower’, 花だ ‘is-flower’, again as per CD).
Since you know both Dolly-先生 and Rubin-先生, I will ask another question. I was watching these videos, and Dolly-先生 argues two things: Firstly, that some uses of で are the Te-form of だ, and secondly, that both で and な are deformations of the coupula だ. In your experience, is this good advice?
I have loved beginning my journey with Bunpro, and really enjoy that it links diverse resources. But Cure Dolly was the first grammar resource I found in Japanese that “clicked” with me, and I am trying to make sure I am not being overly dedicaded to them, since I know there is a lot of controversy about their methodologies,. I am a full time high school foreign language teacher IRL, so a lot of this is not new to me, but Japanese is definitely unique in many ways.
Indeed you will, and its a really nice companion for this long journey!
Curiously enough, I started my journey with Tae Kim and his famous “「です」 is NOT the same as 「だ」” (section 4.1.5 of his book). 
I also used Tofugu quite a lot, its articles are long and detailed by worth it.
I came to Jay Rubin’s ‘Making Sense of Japanese’ (I think with him that ‘Gone Fishin’’ was a much better title) through this very community and agree with the community that the book has to be read after reaching an intermediate level.
That said, the concept that “some uses of で are the て-form of だ” is also in Tofugu (in this article). I would agree with this idea, as it is the way to attach a な-adjective or a noun to another adjective or noun, which is one of the key functions of the て-form.
In relation to “both で and な are deformations of the coupula だ”, I would agree with the former (で as deformation of the copula だ, if by deformation we mean the て-form).
For the latter (な as deformation of the copula だ), I’ve seen in a couple of places (this Tofugu article is one of them) a different theory: that it would be a simplification of にあり, which was used a lot of a time ago for a similar function, thus: にある → なる → な.
Finally, at the end of the day the aim is to express yourself and interact in Japanese, whether it be speaking, reading, listening, or writing. So, if CD “clicks” with you, use it as your guide along with BP and other resources you may find that make sense to you. You might say that, for this journey, the means justify the end. 
なんか毎年夏ごとに、もっと暑くなるような気がする。
It seems like it gets hotter every summer.
Not that there’s anything wrong with yours, but I would translate this as:
“Somehow, every year around Summer, I feel it becomes hotter”
物価が上がり続けるということは言うまでもないけど、給料が上がらない理由は何ですか？
It goes without saying that prices are continually rising, but what is the reason for salaries not increasing?
昨日山で行って、とてもきれいな写真を撮って、湖に泳いだ。
Yesterday I went to the mountains, I took some very beautiful photos and swam in the lake.
私があなたを大好き。
Hi! Good first sentence!
If I may, this would be a more grammatical version: 私はあなたが大好きだ。
“私は”, you are introducing the topic, you are going to talk about you (as for me).
“あなたが”, '大好き’ is a な-adjective, not a verb, so it cannot take ‘を’ as there is no direct object to mark. Think of ‘大好き’ as ‘loveable’, so you can say that what is loveable for you is ‘あなた’, which you identify with ‘が’ (you are loveable).
finally, as ‘大好き’ is a な-adjective, remember you need to mark it as ‘it is’ with ‘だ’.
So the sentence would literally translate as ‘As for me, you are what is loveable’. Thus, ‘I love you’.
もしかしたら来年家族と一緒に日本に旅行するかもしれない。
Maybe I will travel to Japan with my family next year.
Damn, I thought about writing a sentence using the same grammar point, but you got ahead of me 
もう！。。あのやつは絶対に謝ろうとしないよ！そうしたら、俺も謝るわけがない！
Ugh! That guy will never apologize, no matter what! If that’s the case, there’s no way I’m apologizing either!
ごめんね!
I’ve being seeing your sentences and reckon we must be studying exactly the same grammar points と同時に. Actually, it was reading your sentences that gave me the push to go for it.
それで、日本語の例文を書いてくれてありがとうございます、リエアヅさん。 
That’s really cool, let’s keep it up!
Bonus sentence!
コーラは塩が入っていることになんか信じにくい。。。しょっぱいじゃないから！
It’s hard to believe that cola contains salt… because it’s not salty!
Thank you for the in-depth correction, this is hugely helpful.
Day 2:
あれも寿司良くなかった。
That sushi was also not good.
リエアヅさんと同じで、毎日のように一文を書いてみている。
Just like lieath, I try to write a sentence almost every day.
Hi there!
もう一度、nicely done! 残念だった、あの寿司！ 
The only thing I would tweak is ‘あれも寿司’. This does not make real sense in Japanese, it would be said as ‘あの寿司も’, using ‘あの’ instead of ‘あれ’ as you are referring to ‘that sushi’.
頑張ってね！
日本語の文法は難しいが楽しいですね。
Japanese grammar is difficult but fun, isn’t it?
たとえ日本に一度も行かなくても、日本語の勉強をけして止めない。だって、日本語が大好きだよ！
Even if I never go to Japan, I will never stop studying Japanese. Because I really love Japanese!