I will try to help you.
I think the main problem with your strategy is that you have already traced what will happen in the next few months:
Altcoin season, then you take profits in USD, then it comes a bear market, you will put in blockfi.....
You need to consider different scenarios, as we don't know if we are even going to have an altseason like before, or even a so hard bear market. Are you ready for a different scenario like a Bitcoin bull run and altcoins losing even more value?
I think it is too risk to put them in any lending plataform. You will gain 5-10% per year... that is very little in comparinson to 1000% gains bitcoin can still have in the next years, and you risk losing it all.
Certainly. Bitcoin has better perfomance in long term compared to altcoins (in general, few random exceptions). I would consider keeping a hug amount of bitcoin now, at least 50%. Even in a bull market, as altcoins usually lose in AltcoinXBTC ratio in long term.
5. After the bull run should I just put my stablecoins in something like Blockfi during the bear market? Or is cashing out to dollars and investing in something like real estate a good way to defer capital gains taxes?
It depends on your country regulations and laws. In Brazil you don't need to pay taxes if you sell less than 5k USD per month. Additionally, if you are just holding in the bear market you don't have to pay any tax.
Dont worry about taxes in the bear market, just try to survive.