Tender first, pulling a train, not an issue. Tender first propelling the train in front of you a bit more caution is needed, but again not an issue.
At Paddington, it was normal to try and "save" a pilot engine duty on the empty coaching stock to/from Old Oak Common sidings by using a main line loco which was about to do, or had just come from, main line duties. So everything up to a King would be commandeered to bring some stock in tender first, and sit on the buffers heating the train. When the train loco arrived and the train departed, the loco would shunt to its intended main line duty. This accounts for the various photographs of a main line loco sat against the Paddington buffers facing forward with a train ahead of it. The converse happened , to use an arrived loco to move stock tender first out to Old Oak.
Don't forget there are two crew on a steam loco and the fireman has less to do during such manoeuvres, so will commonly be leaning out to assist the driver.
At Taunton, arrivals to the Up bay at the NW end of the station were in a dead end with no run-round. Sidings out west towards the Staplegrove Road bridge were also dead end, so there was no alternative but to push the train back with no pilot loco, which otherwise would end up against the siding buffers. Fireman leaned well out of the cab and shouted all ok to the driver, who just pushed the coaches back at fast walking pace. Meanwhile, shunter is in the forwardmost vestibule, also leaning well out of the droplight to look ahead. and is making slow "shunt back" arm signals, amplified with a fistful of paper towels grabbed from the adjacent toilet!
Sometimes the stock was intended for the sidings over on the Down side instead, and this would take place right across the 4-track main line.
Never an incident.
Crews generally preferred chimney-first working because it avoided coal dust being blown into the cab
David L Smith, in his books about the G&SW 100 years ago, describes how the loco prepared for the Royal Train was derailed. The polished-up standby was 20 miles away. It was driven at over 70 mph tender-first to get there as quickly as possible. Anyone in those days on the footplate who carried goggles would have been seen as a softie!