教えていただく means to have someone teach you. It is the honorific equivalent to おしえてもらう.
もらう means to receive something from somebody, and the person who gives it to you is marked by に.
e.g. お母さんにリンゴをもらった I got an apple from mum
When an action/favour is received, the same concept applies and the person from whom you receive the favour is marked with に
Sorry if my format for an answer is incorrect.
Both can be considered a complete sentence.
(1) implies that development is already in progress, and having the new tech will probably make the originally difficult development no longer difficult. (2) only says that development will probably not be difficult with the new tech, with no indication that the ...
私には the emphasis is on the "I", suggesting that perhaps some other person may be able, but I am not. Typicaly this is regarding some skill.
With が the emphasis would be more neutral, or even focused on the 出来ない．
These forms may also be used in a sense like "I could never do that!"
again emphasis is up to the speaker.
In this context, saying 葉が秋は赤いです instead of 秋は赤いです is not correct, because the 葉 has been already introduced in the discourse (i.e., it's "the leaf", not "a leaf"). If you really want to say 葉 twice, you can do so using は:
(The/This) leaf is red in autumn.
この葉は秋は赤いです。(acceptable but slightly questionable: see ...
If the subject was included, would the phrase look like "葉が秋は赤いです"?
It depends on what you want to focus, but if I had to naturally add the subject in this context, I'd make it topic:
Don't worry, は can be used as many times as needed in a sentence whenever the context fits, for example: