So: I totally understand the impulse to ship Tumblr-Or-Other-Social-Networking-Site users with each other because their blogs and personal styles mesh nicely, and talking about that privately and stuff.
But the blog's not the person, and real people aren't fictional characters, and they can be upset by stuff like that. Particularly non-famous ones who aren't used to that sort of attention.
So, it's usually not a good idea to talk about your real-people ships - even just platonic "these two Steven Universe fanartists should totally be friends!" ones - in places where those real people can see it. Some might be fine with it, but there's a big enough chance that they're going to be uncomfortable that I don't think it's smart to risk it.
And it is pretty much never a good idea to try and make your RL ship canon.
Like, if you want to point Person A at Person B once like "here's a blog you might like if you haven't seen it," fine - you've done your Potential Friendship Diligence.
But don't do stuff like:
* repeatedly reblog Person A's posts about [Insert Shared Interest Here] with notes like "what do you think, Person B? This is your thing, right?"
* repeatedly privately message Person A to ask if they've seen Person B's posts about [Shared Interest], because they're the sort of thing Person A usually responds to
* wonder publicly why Person A isn't responding to Person B's post(s) about [Shared Interest]
* in general, persistently bringing one person to the other's attention despite apparent disinterest
If these two people are really into similar stuff, and they have the same fandoms/circles of acquaintance/whatever, they probably already know about each other. If they're not interacting, it's because they don't want to. This isn't something that you need to fix or investigate.