@TrackDiamond.
The points you mention are all valid.
The main considerations regarding F3/FF with a newly qualified 'Bus driver is essentially not running before you can walk. It is better to consolidate a "standard" technique, get comfortable with it and be familiar with the attitudes/perspectives/power settings etc before moving on. The transition to F3 is not a massive step - but why rush? Get comfortable with FF first.
For those not familiar......there are three main areas to deal with.
Firstly the visual perspective out the window is subtly different. The A319/320 reduces pitch attitude by about 2 degrees as Flap Full runs. A newly qualified pilot needs to get familiar with a "standard" picture out of the window to allow them to concentrate on flying a stable profile, towards the aiming point and then flaring, with a consistent technique, from a known attitude. FF with more drag and associated higher N1 also provides a much more stable platform to achieve this. With F3, the runway sits a lot "lower" (less fields between the nose and the runway) in the visual picture due to the higher pitch attitude - so flare technique needs to be adjusted accordingly.
As someone has already mentioned the 'bus is a lot more slippery in F3 compared to FF which obviously results in less thrust requirement (circa 43% N1). The different "picture", coupled with the lower power gives a much more "unstable" feeling to the approach. If there is minimal headwind component this exacerbates the issues (personally, if there is any tailwind on the approach I simply don't do F3).
Finally the flare is modified because the aircraft pitch attitude is higher - same technique of looking to the end if the runway - but remember the aircraft is "half flared" so a standard flare input on the sidestick will result in a float.......and yes, there is a greater risk of tailstrike.