No signs yet of anything else. Nothing past June 18th is known. The Razowing Jetfighter will probably come up for pre-order earlier. The words in the blue boxes that did not make the pics when I copied them, they give release dates. So we have Scourges, Talos/ Cronos, and Venoms on June 4th, and the Razorwing on June 18th.
Here is a link to the forum thread where you can find the link. There are a couple more pics of wyches and the battleforce box set contents. Warseer forum link. You have to search through the posts to find the link to the posts. I won't post a direct link to the pics.
The images come via spellscape.