How great that you can do something you love full time!
Your art is so vivid, and I'm glad that you have a couple of books to work on.
I am still not published in the kidlit world, but for about a year, I've been soaking in online portfolios and reading lots and lot of articles about what to include/exclude, so this advice is based on that. Not on personal success or my own major publishing contract or anything.
Also, I looked at your website the day you wrote the most recent post, but I didn't have time to write anything that day. I just looked again, and some of the things I noticed are already better.
Could you add a few more girls? Maybe try to add kids of other races? I've read that publishers look for that.
The kid getting eaten by a monster coming out of a book probably makes sense in context, but it would make my kids scared of books. Could the monster break out of a TV or video game console instead?
I love the mummy snowboarding. I like all the monsters on vacation, actually. Could you add a beginning and end to make it into a story? Like, the three of them packing or at a travel agency? And at the end they could all come home to a porch full of mail and newspapers because none of them thought to ask the neighbors to check the mail.