Hi and welcome.
Interesting question, and quite an undertaking.
I am a little confused as you state HFT which is predominantly for hunting style rifles which can be picked up for not a lot of money. Appreciate if you want to get higher up in the classes (leagues) you would probably evolve your kit but there is no need to. FT is another ball game altogether and does have a fair bit of hand built custom stuff around but again it is not necessary - good Glass however is always a good investment.
You need a good quality PCP with single shot capability and some medium to good glass to fit on top - that's really all. Obviously a bottle and bag etc but at least you then have your first year or so covered.
Air arms 200 or 400 series can be got for not a lot of money. I got my HW100 for £390 as it needed work.
What budget do you have - or is the build just for fun and you are pretty handy then all the above will not apply.
FTP900 +Sightron S111 10-50 x 55
AA Pro Target in FWB FP70 stock + MTC Mamba lite
Daystate Airwolf + Bushnell Elite 6500
" life is about the memories we hold and not the things that we own"