The system cannot differentiate between a commercial fare and a hotline fare - which is a reduced commercial fare- which is why the avios/tier points are deposited- however the rule is no. 30 bookings per year- up to 9 pax per booking. All are encouraged to offer hotlines. There are also hotlines for hotels/cars and tours with no limit. And only a POU (proactive upgrade) can be done at counter if offered on long hauls only- no SEA/LAX/SFO.

And no a GUFF cannot be applied to a hotline- it is considered a promotion on top of a promotion.
No umnr service on hotlines either. Hotlines can be purchased in all cabins- included connections with oneworld (AA and IB) alliances although this makes the hotline value less. Stay on BA metal for the best price.

It is called a hotline ticket and does show the staff number/date of join from the staff.
The rules of the fare are commercial rules (ex. chg fee 275.00USD/ of 100 GBP and any fare differential if different bucket for chg) etc.