hey R,
regarding 1, IMO a swim focus can be great. Matt Dixon’s books have some good stuff on how to structure a ‘post-season’, or in other words, how to prepare to have a great season. I wouldn’t advise to repeat the same base plan twice, rather check out SSB or Traditional base. also check out the thread Long term plan for a 70.3 A race next August which is on 70.3 but the stuff transfers to full distance
with 2, I let the experienced full distance people chip in, but the TR plans should prepare you well - you will build fitness in the same way and then race at a bit lower %.
cheers and good luck