Hole in copper pipe, solder under floor, T coupling & protection

[dreikher]

I was stupid enough not to check the position of the pipes under the tiles when installing a toilet and drilled right through the center of a 16 mm copper water pipe. I exposed the pipe by removing a ~30cm section of the plastic sleeve and a ~10 cm section of the pipe around the hole. Several questions:

• I was thinking to solder, but not sure if I should be brazing or is soldering enough for peace of mind (I'm in France, but I guess nobody will open up the floors for inspection, so for me allowed by code in UK/US is good enough).
• I know I should use a sleeve, but not sure how to secure it properly because if I put it on before I solder it'll melt. The alternative is to use some kind of tape. I guess Denso tape is good for that? If so, any special way of securing it to the edges of the sleeve from both sides of the exposed pipe?
• I made a small cut in a sleeve around another pipe running close by (no damage to the pipe). Can I use regular silicone to seal that hole to avoid direct contact of the pipe with the surrounding concrete?
• I was thinking to use the opportunity to solder an extension from the pipe using a T coupling under the floor to connect a water line to the new toilet. What do you think about copper T couplings inside concrete? How can I protect the area around the coupling with a sleeve? Are there T-shaped sleeve connectors or something similar?

Thanks very much to anyone who can help!