yeah u can clone 2 weeks into flowering ive done it as late as week 4. it will just take longer to root caz it has to revert to veggin again. i wouldnt top during flowering but it can be done, if you want to top caz the plant is getting to high try LST. but if u need clones then top it and use the cutting as a clone. but the less u mess withit during the flowering the better. if u are going to top and get clones do it all at the same time so the plant can heal itself in 1 go.
You can take the clones, but you gotta "re-veg" em by putting-em under 24s. The stress change will cause the roots longer to root, but it will work. As far as topping during flowering...NO haha. That's what the veg. stage is for.