My MDFloatLayout and its properties isnt displaying on the screen

Most of your widgets in the kv you posted fill the entire screen, hiding anything behind them. Note that the default size_hint is (1,1). Also, the pos_hint for the MDLabel:

pos_hint: {'center_x': .23, 'center_y':2.9}

sets the center of the MDLabel well beyond the top of the display.

Try changing size_hint from the default and adjusting pos_hint. Not knowing what your goal is, I have modified your kv just to make everything visible:

MDFloatLayout:
    MDFloatLayout:

        pos_hint: {'center_x':0,'center_y': 1.2}
        canvas.before:
            Color:
                rgb: (132/255, 0, 117/255, 0)
            Ellipse:
                pos: self.pos
                size: self.size[0]*2, self.size[0]/1.75
                source: "test.jpg"


    #This MDLabel is one of the contents not being displayed
    MDLabel:
        pos_hint: {'right': 1, 'y':0}
        size_hint: 0.2, 0.2
        text: '568 followers'
        bold: True

    MDFloatLayout:
        pos_hint: {'center_x':0, 'center_y':0}
        size_hint: 0.5, 0.5
        canvas:
            Color:
                rgb: (223/255, 237/255, 240/255, 0)
            Ellipse:
                pos: self.pos
                size: self.size[0]*2, self.size[0]* 1.95

#This FloatLayout below isnt being displayed too
    MDFloatLayout:
        size_hint: None, None
        size: dp(200), dp(240)
        pos_hint: {'center_x': .3, 'center_y':.3}
        radius: [dp(20)]*4
        md_bg_color: 250/255, 250/255, 250/255, 0