Run the following snippet on J2D and some other (ES2, D3D) pipeline
public class FXSwing {
    private static void initAndShowGUI() {
        String url = "file:///Users/felipe/Documents/fonts/CrashLandingBB.ttf";
        final Font jxFont = Font.loadFont(url, 36);
        java.awt.Font awtFont = new java.awt.Font(jxFont.getName(), java.awt.Font.PLAIN, 36);
        JFrame frame = new JFrame("FX");
        final JFXPanel fxPanel = new JFXPanel();
        JLabel jlabel = new JLabel("my swing label");
        jlabel.setFont(awtFont);
        JSplitPane splitter = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, fxPanel, jlabel);
        splitter.setBackground(java.awt.Color.WHITE);
        splitter.setDividerLocation(300);
        frame.add(splitter);
        Platform.runLater(new Runnable() {
            public void run() {
                VBox box = new VBox();
                box.setAlignment(Pos.CENTER_LEFT);
                Text text = new Text("my jfx text");
                text.setFont(jxFont);
                box.getChildren().add(text);
                Scene scene = new Scene(box, 200, 200, Color.WHITE);
                fxPanel.setScene(scene);
            }
        });
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(600, 200);
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                initAndShowGUI();
            }
        });
    }
}

The call to java.awt.Font awtFont = new java.awt.Font(jxFont.getName(), java.awt.Font.PLAIN, 36); only creates the "CrashLanding" font on the J2D pipeline.