LISA/HTB Bonuses-US Tax Implications?

So, I (stupidly) opened a Stocks and Shares LISA. From my understanding, I don't need to file anything from capital gains until I close the account, so that is a problem 2 years from now!  I lost money on it anyway during the tax year of 2018. Just wanted to make sure that my understanding of this is correct?

And then to my main question: how do you treat the UK government bonuses on any type of LISA or HTB ISA? Is it interest income? Capital gains? 1099-MISC? Does it matter what type of account the government bonus was paid into?

I have very little knowledge of PFICs, LISAs, or the HTB scheme. I can offer some suggestions as to where to start investigations.

Stocks and Shares ISA:
You will first have to determine if the S&S ISA is a PFIC. The ISA is only a name for the wrapper containing the actual investment products. If the actual investments are PFICs, then form 8621 must be filed. Hint: the odds are very good that the underlying investments are a PFIC. The accounting method used is critical as PFICs can be subject to a very high tax rate. My understanding is yearly reporting is the preferred method. If one waits till the second or third year, the computations required can be exceptionally challenging.

https://www.taxesforexpats.com/guides/passive-foreign-investment-company-8621.html

https://thunfinancial.com/home/american-expat-financial-advice-research-articles/why-americans-should-never-ever-own-shares-in-a-non-us-incorporated-mutual-fund/

https://www.goldinglawyers.com/pfic-rules-2018-is-your-foreign-investment-a-u-s-tax-trap/

https://www.irs.gov/pub/irs-prior/f8621--2015.pdf

LISA:
Only one main concern - is a LISA a pension plan? Would the US treat a LISA as a pension plan? There are withdrawal restrictions, but are these enough. Other concern is the UK Govt. contribution, which is not an employer contribution. I would suggest definitely not trying to claim it as interest. Very grey area.

https://www.gov.uk/lifetime-isa

HTB:
Another grey area but possibly more straightforward for reporting. Is the selected scheme a PFIC? If so, major problem. If it's a bank account it could be less of a problem with the UK Govt. contribution treated as ordinary income on a return (which cannot be included in FEIE - form 2555, and of course, there is no tax to offset on FTC - form 1116), in addition to declaring the yearly interest gained on Schedule B.

https://www.gov.uk/affordable-home-ownership-schemes/help-to-buy-isa

With the exception of PFICs, all a very grey and challenging area, even for the professionals, which is probably why there have been no responses to your question.