So far colors that may be offered to the Deities, all colors may be utilized just suitable to your scheme. But black should not be used for the Deities dresses or for Temple decorations.
Krishna as He is appearing in our Temples is in the Kisora age, and the dress which I have introduced is His dress of Kisora age. In our Temples the Deities, Radha and Krishna are worshiped as Laksmi-Narayana with all the opulences of Their Majestic Lordship in Dvaraka. The worship of Radha-Krishna as They appear in Vrndavana is a very advanced stage, so we worship Them in the Temples as Laksmi-Narayana. Actually there is no difference because Laksmi-Narayana is directly the expansion of Radha-Krishna. We are following the prescribed method of Temple worship as it is the effective program for developing the highest perfection of pure love of Krishna.
If Prasadam is to be honored in the Temple room, the curtains may be drawn before the Deities while the devotees are taking Prasadam. The best arrangement is to honor Prasadam in a separate room for the purpose, if possible.
The arati articles may be returned to the same places, especially the conch shell, but the deeps, lamps, should be set down from their places because they must be washed.
I am very glad to learn that the three girls from France are advancing nicely under your tutelage. Please continue to train them up to chant regularly and to always keep engaged in Krishna activities. As ideal householder girl, you are giving them the best example of Krishna conscious life. Please offer my blessings to them and to all the devotees.