It has been officially announced today, you have the three till January.
http://www.heartsfc....2241384_2523171
If you dont mind as a jambo, putting some information about the three. I regularly attend the Hearts under 19s game (place to go if you want to see a Hearts team playing well and usually beating teams.) The three players you have are the best 3 players in our 19s (a team currently topping the table.) I cant confess to have followed Raith Rovers too closely this season, however it was interesting to hear on the Terrace podcast that part of your problem is that McGlynn has failed to adapt the team without Tade and instead just launches the ball up the park. Well the good news is you have 3 players that allow you to play a different system.
The three players are used to playing with the ball on the ground, with quick passing and movement. And can also press quickly upon the opposition when the opposition has the ball.
Jason Holt is the pick of the three, Scottish under 19 player of the year last season. He has played a number of times for the Scotland under 19s and was also called up last month as a replacement in the Under 21 side. He is a CM who can be sitting alongside a defensive midfielder or more attacking behind the striker. Though he is tiny and looks like the side of a piece of paper he has been able to hold his own against guys much bigger then himself (though I imagine it may be a sharp learning curve for the first game or two.) He is a skillful player, has been compared to Barry Ferguson (before he went to Blackburn and was actually an amazing player.) He can hold onto the ball then pass it to the right person and nearly all the time it will go to that player. He also is very good running with the ball with at his feet and go direct through the centre of the park. He also is good at striking it outside the box (though he hasn't scored this season from that position.) Last season he scored 7 goals for the under 19s. He is an intelligent player and has good movement.
Jamie Walker is a player who can play on the wings, upfront or even in the middle in an attacking midfield role. He was described two seasons ago by the head of our Youth Development as the best player he had seen through the academy in 15 years. Unfortunantly last season he missed most of the season with a bad injury (but in a handful of games (6 or 7) still scored 5 goals), but after missing the first few games this season has been getting better with each game. He is a player who likes to go forward, can be quite tricky and like most Wingers can be greedy at times. He is great ability and will always be looking for a chance to score or set others up. He has a great strike on him.
David Smith is another player who can play in the middle of midfield but is mainly used as a left winger or a striker. He may not be quite as skillful as the other two but he still has plenty of ability. He is quick and is quite direct with his running at defences. He is a decent passer of the ball and has a great shot on him. He is an Scotland Under 19 internationalist (has also been an U17 and U16.)
I see from reports that Denis Prychnenko has had a poor start for you since he came in. I would say dont write him off too quickly yet, a few times when he has been with competitive football for a few weeks (or in his case 6 months) he has been quite poor to start of, but over a few games he picks it up and is a handy player. I think he has found the first division a shock, but if he fails it wont be for not trying as he is a very hard worker, last season there were plenty of stories of coaches having to force him off the training ground as he had been staying behind so late to work on things and it also rubbed off on the other 19s players who upped the training level to be like him.
I would caution expecting anything too quickly from these players, for the 3 new guys it is there first full experence of senior football (though Jason Holt and David smith got 10 and 20 minutes respectively in the last game of last season against Dundee United) so it may take a few games before they are up and running.
With our policy from January looking like it is scrap most first team players and bring in youth, hopefully the loan period at Raith is very fruitful for them and hopefully gets you points to move up the table. Hopefully we can send more top youngsters to help you (and you help us by aiding their development) as there are a few other under 19s close to making the step up (I think one or both of our full backs will be the next to go up, you dont happen to need one do you (even a left back who used to be a Dunfermline youngster...)
edit: just noticed my fellow youth reporter from Hearts has already posted with much the same, oh well, hope this adds anything on top of what he says.