Cactus Bouncer

This card cannot be Special Summoned. While a Plant-Type monster other than this card is face-up on the field, neither player can Special Summon monsters.

My question: If I have Bouncer and one other plant, Can I sill use Fallen Angel's/Birdman's eff to return it to my hand and SS it?

I second Pox.

Taking a different but similar situation, you cannot Special Summon Lava Golem/Volcanic Queen when Archlord Krystia is on the field, even if you should be using Krystia as the cost. You can't even attempt to Special Summon due to Krystia's effect, hence you cannot pay the cost.

Extrapolating from that, you cannot return Cactus Bouncer to hand to Special Summon Fallen Angel/Birdman.

Cactus Bouncer (+ another plant in play) prevents special summoning so you can't even attempt to SS Birdman.

is it like if i have Ritual Monster that ritual summoned by banish Djinn Releaser, my opponent can't tribute Ritual Monster to special summon Volcanic Queen?

Yes, since Releaser prevents your opponent from any attempt to special summon monsters.

So I can't use him and the other plant as a synch/xyz summon?

No.

while special summons are being prohibited, you cannot even attempt to special summon, even if the process for special summon would remove the prohibiting card from the field.