Then I will gladly answer the questions~!
1. I would absolutely love to take part in a competition/anthology that isn't mine~! They can be a little bit tough to run, though, so, if you want any advice on setting them up, I'm happy to help out.
(Although the themes you suggested further down sound a bit stressful for me to write, personally. I wouldn't enjoy writing terribly cliche BL and I'd feel a lot of pressure trying to avoid anything cliche altogether.)
2. My history with BL is... Long. Boringly so.
Back in my young childhood, the internet was a completely optional thing, so my parents chose not to have it for several years. I used my computer to entertain myself by writing. When we finally got internet access, I went merrily searching around Google for images of all my favourite stuff, including Yugioh, and... Stumbled across a picture of Yami x Yugi and, despite having been trained to believe it was horrible, couldn't look away. And somehow from there I ended up reading a lot of slash fic?
So I had my start binging fanfiction, and from there I spread to Smackjeeves, DeviantArt, Tumblr, various manga reading sites, probably other places I no longer remember, and eventually to Novel Updates.
I came to Scribble Hub directly from Novel Updates when this site was first made.
As for writing BL... The more I read BL, the more I just added queer men to my own writing naturally. I'm also a roleplayer and I've been playing in-depth roleplaying games with one particular friend for at least a decade now. They amount to turn-based collaborative writing stories and we stuffed them full of queer people (being queer ourselves).
Therefore I've been writing BL for more than a decade (but miraculously never wrote anything that I released for public reading, to my memory).
These days I'm much more into GL, since I've become picky and I can rarely find a BL to satisfy me. I've hit that stage where I have to just write it myself.
(I actually run the Yuri Garden on NUF, and we run various events that get advertised over here too.)
Types of BL I like and hate... Well, I really hate Omegaverse BL (but love Omegaverse GL?), I hate BL that literally treats the more feminine partner as if they were a woman (calling them "wife" and stuff), and I hate strict uke/seme dynamics. At the same time, I have no interest in extremely masculine men...
I like BL with refreshing dynamics and where men are allowed to fall more naturally along the spectrum of gender and gender expression, and where the relationships are a little bit deeper.
Also I have a terrible curse where I almost always write non-human beings, mpreg, general bizarreness, and trauma victims trying to heal from their past.