(B), There are quite a few native speakers of English whose writing is superb but who can't spell worth a damn. I have often wished that these folks would give edit permission on their blog to a fan or two who could sneak in and edit the grammar. If you can find (or hire, cheap) a person who will do this for you, there's nothing wrong with it. Pro writers all have editors... usually several editors.
But you'll find that it's easier to want cheap or free editorial help than it is to find it. So don't worry too much about it. See Step A.
(C) Your English reads just fine to me.
(D) Why not blog in your native language occasionally, as well as in English? There's nothing wrong with having more than one blog.
One big point of blogs is to wrangle over your own ideas by writing them down. You might as well do that in a language which you are comfortable using.
There may be other native speakers of your language who would be ecstatic if a tech blogger showed up and started writing things that they could read comfortably.
Not that I don't understand why you'd prefer to use English for a lot of things, just as many people prefer to do their writing on news.yc and live in a startup hub.
If you are so self conscious about it, why don't you just put a disclaimer at the top of every post, e.g. something short like "Please note: English is not my first language."
I guess you could start by putting a disclaimer on your blog stating that English is not your first language, and probably asking a friend/colleague to review your post prior to posting it. But I do think that this should not stop you from sharing your ideas or thoughts. Someone's fluency with English would (IMO) not stop people from reading what you have to say.
Good luck. Hope this helps.
So I guess I agree with everybody else - just write your blog. If it's informative and fun to read, people will read it.
Language should be the last reason why one does not communicate. An idea holds itself regardless of which language its written in and with what finesse.
And like you I guess I too shift from philosophy to poetry to tech without missing a beat. It does restrict your reader base a lot but again, if your style can accommodate all these perspectives, I dont see why you could not talk about all that catches your fancy.
So if you stick to solid stuff and stay away from gossip and other nonsense you'll be fine.
I know a lot of native english speakers whos english on their blog is crap. I wouldn't worry about it.