I'm struggling a bit to get my head round your questions but before that
As we all know conspicuity must be treated as unvalidated and unverified and as it is not discreet cannot be deemed identified.
I don't see any reason why a target that is on a conspicuity code cannot be considered identified - as long as you have it properly identified. Take, for example, an aircraft given to you in a radar handover - you have the ident but don't want to use your limited supply of #s so put it on a conspicuity code. It's still indentified. Taking this one step futher, there's no reason not to apply positive radar control/separation to two targets that you have identified even though they're on conspicuity codes and other units would have to avoid them by a wider margin. It's not an ideal situation but if the CAA won't give you the code blocks you need to put your traffic on discrete codes, what can you do???? (I'm assuming that you will still have PSR and are controlling the primary targets.)
Q1 Can the conspicuity be asked to squawk ident if no inference of radar service is implied to assist in discharging our responsibilities with the PAX, Jet, RAS traffic that this FIS is going to be in conflict with? and an agreed level cap be applied.
The good book (Section 1, chapter 5, para 4.1 c)) say's you cannot identfy a target with the SPI function if it's on a conspicuity code - whether you offer it a radar service or not is irrelevant. Of course, there's nowt to stop you identifying it with a turn (subject to all the usual cautions) if that will help you to provide a better service to other traffic that you're handling).
Q2 Is it practical, safe, legal, a good idea to change the potential FIS confliction to a discreet code( if you have any left), ensure that no service is implied and then when it is no longer a confliction change it back to the conspicuity.
Practical? It's a matter of time usually. If you know you've got a conflict coming up and identing an aircraft on a FIS will help sorting out the big picture then I would probably do it - otherwise I don't get any benefit for the effort. The bit about ensuring that the pilot understands that he/she is not now getting a radar service might take up some of that valuable time too!
Safe? Don't see why not.
legal? Can't think of any rules that say no.
Good idea? If it helps with the big picture and the work involved is not disproportionate, why not?
Q3 How does the LCE team help the troops to ensure that the new data on the displays does not tempt them into taking FRISING to the next level of using modes A and C to expedite the Jet RAS traffic by keeping the pesky FIS’s out the way??? and reducing the willingness to not seek to achieve 5 nm etc.
Easy one. Good knowledge
and understanding of the rules - and professionalism all round.